Install from closure: wording and fallback using .bash_profile

- use empty ~/.bash_profile if it's not there - use "source" instead of vague "." - make it explicit how to start using Nix after installation
Drop a few more references to all-packages.nix
2017-01-25 19:21:57 +01:00 · 2017-01-03 16:42:24 +01:00 · 2017-01-03 11:42:56 +01:00 · 2017-01-03 11:40:51 +01:00 · 2017-01-03 10:08:15 +01:00 · 2017-01-03 10:11:09 +02:00
479 changed files with 30273 additions and 22992 deletions
@@ -0,0 +1,16 @@
+((c++-mode . (
+  (c-file-style . "k&r")
+  (c-basic-offset . 4)
+  (indent-tabs-mode . nil)
+  (tab-width . 4)
+  (show-trailing-whitespace . t)
+  (indicate-empty-lines . t)
+  (eval . (c-set-offset 'innamespace 0))
+  (eval . (c-set-offset 'defun-open 0))
+  (eval . (c-set-offset 'inline-open 0))
+  (eval . (c-set-offset 'arglist-intro '+))
+  (eval . (c-set-offset 'arglist-cont 0))
+  (eval . (c-set-offset 'arglist-cont-nonempty '+))
+  (eval . (c-set-offset 'substatement-open 0))
+  (eval . (c-set-offset 'access-label '-))
+  )))
@@ -8,7 +8,6 @@ Makefile.config
 /nix.spec
 /stamp-h1
 /svn-revision
-/NEWS
 /libtool

 /corepkgs/config.nix
@@ -32,35 +31,14 @@ Makefile.config
 /doc/manual/*.5
 /doc/manual/*.8
 /doc/manual/version.txt
-/doc/manual/release-notes.html

 # /scripts/
 /scripts/nix-profile.sh
-/scripts/nix-pull
-/scripts/nix-push
-/scripts/nix-switch
-/scripts/nix-collect-garbage
-/scripts/nix-prefetch-url
-/scripts/nix-install-package
-/scripts/nix-channel
-/scripts/nix-build
 /scripts/nix-copy-closure
-/scripts/nix-generate-patches
-/scripts/NixConfig.pm
-/scripts/NixManifest.pm
-/scripts/GeneratePatches.pm
-/scripts/download-using-manifests.pl
-/scripts/copy-from-other-stores.pl
-/scripts/download-from-binary-cache.pl
-/scripts/find-runtime-roots.pl
 /scripts/build-remote.pl
 /scripts/nix-reduce-build
 /scripts/nix-http-export.cgi

-# /src/bsdiff-4.3/
-/src/bsdiff-4.3/bsdiff
-/src/bsdiff-4.3/bspatch
-
 # /src/libexpr/
 /src/libexpr/lexer-tab.cc
 /src/libexpr/lexer-tab.hh
@@ -71,28 +49,38 @@ Makefile.config

 # /src/libstore/
 /src/libstore/schema.sql.hh
+/src/libstore/sandbox-defaults.sb
+
+/src/nix/nix

 # /src/nix-env/
 /src/nix-env/nix-env

-# /src/nix-hash/
-/src/nix-hash/nix-hash
-
 # /src/nix-instantiate/
 /src/nix-instantiate/nix-instantiate

-# /src/nix-log2xml/
-/src/nix-log2xml/nix-log2xml
-
 # /src/nix-store/
 /src/nix-store/nix-store

+/src/nix-prefetch-url/nix-prefetch-url
+
 # /src/nix-daemon/
 /src/nix-daemon/nix-daemon

+/src/nix-collect-garbage/nix-collect-garbage
+
+# /src/nix-channel/
+/src/nix-channel/nix-channel
+
 # /src/download-via-ssh/
 /src/download-via-ssh/download-via-ssh

+# /src/buildenv/
+/src/buildenv/buildenv
+
+# /src/nix-build/
+/src/nix-build/nix-build
+
 # /tests/
 /tests/test-tmp
 /tests/common.sh
@@ -109,12 +97,18 @@ Makefile.config

 /misc/systemd/nix-daemon.service
 /misc/systemd/nix-daemon.socket
+/misc/upstart/nix-daemon.conf
+
+inst/

 *.a
 *.o
 *.so
+*.dll
+*.exe
 *.dep
 *~
+*.pc

 # GNU Global
 GPATH
@@ -1,8 +0,0 @@
-The following people contributed to Nix, in alphabetical order:
-
-Martin Bravenboer
-Eelco Dolstra
-Niels Janssen
-Armijn Hemel
-Rob Vermaas
-Eelco Visser
@@ -1,229 +0,0 @@
-Copyright 1994, 1995, 1996, 1999, 2000, 2001, 2002 Free Software
-Foundation, Inc.
-
-   This file is free documentation; the Free Software Foundation gives
-unlimited permission to copy, distribute and modify it.
-
-Basic Installation
-==================
-
-   These are generic installation instructions.
-
-   The `configure' shell script attempts to guess correct values for
-various system-dependent variables used during compilation.  It uses
-those values to create a `Makefile' in each directory of the package.
-It may also create one or more `.h' files containing system-dependent
-definitions.  Finally, it creates a shell script `config.status' that
-you can run in the future to recreate the current configuration, and a
-file `config.log' containing compiler output (useful mainly for
-debugging `configure').
-
-   It can also use an optional file (typically called `config.cache'
-and enabled with `--cache-file=config.cache' or simply `-C') that saves
-the results of its tests to speed up reconfiguring.  (Caching is
-disabled by default to prevent problems with accidental use of stale
-cache files.)
-
-   If you need to do unusual things to compile the package, please try
-to figure out how `configure' could check whether to do them, and mail
-diffs or instructions to the address given in the `README' so they can
-be considered for the next release.  If you are using the cache, and at
-some point `config.cache' contains results you don't want to keep, you
-may remove or edit it.
-
-   The file `configure.ac' (or `configure.in') is used to create
-`configure' by a program called `autoconf'.  You only need
-`configure.ac' if you want to change it or regenerate `configure' using
-a newer version of `autoconf'.
-
-The simplest way to compile this package is:
-
-  1. `cd' to the directory containing the package's source code and type
-     `./configure' to configure the package for your system.  If you're
-     using `csh' on an old version of System V, you might need to type
-     `sh ./configure' instead to prevent `csh' from trying to execute
-     `configure' itself.
-
-     Running `configure' takes awhile.  While running, it prints some
-     messages telling which features it is checking for.
-
-  2. Type `make' to compile the package.
-
-  3. Optionally, type `make check' to run any self-tests that come with
-     the package.
-
-  4. Type `make install' to install the programs and any data files and
-     documentation.
-
-  5. You can remove the program binaries and object files from the
-     source code directory by typing `make clean'.  To also remove the
-     files that `configure' created (so you can compile the package for
-     a different kind of computer), type `make distclean'.  There is
-     also a `make maintainer-clean' target, but that is intended mainly
-     for the package's developers.  If you use it, you may have to get
-     all sorts of other programs in order to regenerate files that came
-     with the distribution.
-
-Compilers and Options
-=====================
-
-   Some systems require unusual options for compilation or linking that
-the `configure' script does not know about.  Run `./configure --help'
-for details on some of the pertinent environment variables.
-
-   You can give `configure' initial values for configuration parameters
-by setting variables in the command line or in the environment.  Here
-is an example:
-
-     ./configure CC=c89 CFLAGS=-O2 LIBS=-lposix
-
-   *Note Defining Variables::, for more details.
-
-Compiling For Multiple Architectures
-====================================
-
-   You can compile the package for more than one kind of computer at the
-same time, by placing the object files for each architecture in their
-own directory.  To do this, you must use a version of `make' that
-supports the `VPATH' variable, such as GNU `make'.  `cd' to the
-directory where you want the object files and executables to go and run
-the `configure' script.  `configure' automatically checks for the
-source code in the directory that `configure' is in and in `..'.
-
-   If you have to use a `make' that does not support the `VPATH'
-variable, you have to compile the package for one architecture at a
-time in the source code directory.  After you have installed the
-package for one architecture, use `make distclean' before reconfiguring
-for another architecture.
-
-Installation Names
-==================
-
-   By default, `make install' will install the package's files in
-`/usr/local/bin', `/usr/local/man', etc.  You can specify an
-installation prefix other than `/usr/local' by giving `configure' the
-option `--prefix=PATH'.
-
-   You can specify separate installation prefixes for
-architecture-specific files and architecture-independent files.  If you
-give `configure' the option `--exec-prefix=PATH', the package will use
-PATH as the prefix for installing programs and libraries.
-Documentation and other data files will still use the regular prefix.
-
-   In addition, if you use an unusual directory layout you can give
-options like `--bindir=PATH' to specify different values for particular
-kinds of files.  Run `configure --help' for a list of the directories
-you can set and what kinds of files go in them.
-
-   If the package supports it, you can cause programs to be installed
-with an extra prefix or suffix on their names by giving `configure' the
-option `--program-prefix=PREFIX' or `--program-suffix=SUFFIX'.
-
-Optional Features
-=================
-
-   Some packages pay attention to `--enable-FEATURE' options to
-`configure', where FEATURE indicates an optional part of the package.
-They may also pay attention to `--with-PACKAGE' options, where PACKAGE
-is something like `gnu-as' or `x' (for the X Window System).  The
-`README' should mention any `--enable-' and `--with-' options that the
-package recognizes.
-
-   For packages that use the X Window System, `configure' can usually
-find the X include and library files automatically, but if it doesn't,
-you can use the `configure' options `--x-includes=DIR' and
-`--x-libraries=DIR' to specify their locations.
-
-Specifying the System Type
-==========================
-
-   There may be some features `configure' cannot figure out
-automatically, but needs to determine by the type of machine the package
-will run on.  Usually, assuming the package is built to be run on the
-_same_ architectures, `configure' can figure that out, but if it prints
-a message saying it cannot guess the machine type, give it the
-`--build=TYPE' option.  TYPE can either be a short name for the system
-type, such as `sun4', or a canonical name which has the form:
-
-     CPU-COMPANY-SYSTEM
-
-where SYSTEM can have one of these forms:
-
-     OS KERNEL-OS
-
-   See the file `config.sub' for the possible values of each field.  If
-`config.sub' isn't included in this package, then this package doesn't
-need to know the machine type.
-
-   If you are _building_ compiler tools for cross-compiling, you should
-use the `--target=TYPE' option to select the type of system they will
-produce code for.
-
-   If you want to _use_ a cross compiler, that generates code for a
-platform different from the build platform, you should specify the
-"host" platform (i.e., that on which the generated programs will
-eventually be run) with `--host=TYPE'.
-
-Sharing Defaults
-================
-
-   If you want to set default values for `configure' scripts to share,
-you can create a site shell script called `config.site' that gives
-default values for variables like `CC', `cache_file', and `prefix'.
-`configure' looks for `PREFIX/share/config.site' if it exists, then
-`PREFIX/etc/config.site' if it exists.  Or, you can set the
-`CONFIG_SITE' environment variable to the location of the site script.
-A warning: not all `configure' scripts look for a site script.
-
-Defining Variables
-==================
-
-   Variables not defined in a site shell script can be set in the
-environment passed to `configure'.  However, some packages may run
-configure again during the build, and the customized values of these
-variables may be lost.  In order to avoid this problem, you should set
-them in the `configure' command line, using `VAR=value'.  For example:
-
-     ./configure CC=/usr/local2/bin/gcc
-
-will cause the specified gcc to be used as the C compiler (unless it is
-overridden in the site shell script).
-
-`configure' Invocation
-======================
-
-   `configure' recognizes the following options to control how it
-operates.
-
-`--help'
-`-h'
-     Print a summary of the options to `configure', and exit.
-
-`--version'
-`-V'
-     Print the version of Autoconf used to generate the `configure'
-     script, and exit.
-
-`--cache-file=FILE'
-     Enable the cache: use and save the results of the tests in FILE,
-     traditionally `config.cache'.  FILE defaults to `/dev/null' to
-     disable caching.
-
-`--config-cache'
-`-C'
-     Alias for `--cache-file=config.cache'.
-
-`--quiet'
-`--silent'
-`-q'
-     Do not print messages saying which checks are being made.  To
-     suppress all normal output, redirect it to `/dev/null' (any error
-     messages will still be shown).
-
-`--srcdir=DIR'
-     Look for the package's source code in directory DIR.  Usually
-     `configure' can determine that directory automatically.
-
-`configure' also accepts some other, not widely useful, options.  Run
-`configure --help' for more details.
-
@@ -5,24 +5,37 @@ makefiles = \
  src/libstore/local.mk \
  src/libmain/local.mk \
  src/libexpr/local.mk \
-  src/nix-hash/local.mk \
+  src/nix/local.mk \
  src/nix-store/local.mk \
  src/nix-instantiate/local.mk \
  src/nix-env/local.mk \
  src/nix-daemon/local.mk \
-  src/download-via-ssh/local.mk \
-  src/nix-log2xml/local.mk \
-  src/bsdiff-4.3/local.mk \
+  src/nix-collect-garbage/local.mk \
+  src/nix-prefetch-url/local.mk \
+  src/buildenv/local.mk \
+  src/resolve-system-dependencies/local.mk \
+  src/nix-channel/local.mk \
+  src/nix-build/local.mk \
  perl/local.mk \
  scripts/local.mk \
  corepkgs/local.mk \
  misc/systemd/local.mk \
+  misc/launchd/local.mk \
+  misc/upstart/local.mk \
  misc/emacs/local.mk \
  doc/manual/local.mk \
  tests/local.mk
+  #src/download-via-ssh/local.mk \

-GLOBAL_CXXFLAGS += -std=c++0x
+GLOBAL_CXXFLAGS += -std=c++11 -g -Wall

-include Makefile.config
+-include Makefile.config
+
+OPTIMIZE = 1
+
+ifeq ($(OPTIMIZE), 1)
+  GLOBAL_CFLAGS += -O3
+  GLOBAL_CXXFLAGS += -O3
+endif

 include mk/lib.mk
@@ -3,18 +3,21 @@ CC = @CC@
 CFLAGS = @CFLAGS@
 CXX = @CXX@
 CXXFLAGS = @CXXFLAGS@
-HAVE_OPENSSL = @HAVE_OPENSSL@
+ENABLE_S3 = @ENABLE_S3@
+HAVE_SODIUM = @HAVE_SODIUM@
+LIBCURL_LIBS = @LIBCURL_LIBS@
 OPENSSL_LIBS = @OPENSSL_LIBS@
 PACKAGE_NAME = @PACKAGE_NAME@
 PACKAGE_VERSION = @PACKAGE_VERSION@
+SODIUM_LIBS = @SODIUM_LIBS@
+LIBLZMA_LIBS = @LIBLZMA_LIBS@
+SQLITE3_LIBS = @SQLITE3_LIBS@
 bash = @bash@
 bindir = @bindir@
 bsddiff_compat_include = @bsddiff_compat_include@
+curl = @curl@
 datadir = @datadir@
 datarootdir = @datarootdir@
-dblatex = @dblatex@
-docbookrng = @docbookrng@
-docbookxsl = @docbookxsl@
 docdir = @docdir@
 exec_prefix = @exec_prefix@
 includedir = @includedir@
@@ -29,6 +32,6 @@ pkglibdir = $(libdir)/$(PACKAGE_NAME)
 prefix = @prefix@
 storedir = @storedir@
 sysconfdir = @sysconfdir@
-w3m = @w3m@
+doc_generate = @doc_generate@
 xmllint = @xmllint@
 xsltproc = @xsltproc@
@@ -1,10 +0,0 @@
-Nix is a purely functional package manager.  For installation and
-usage instructions, please read the manual, which can be found in
-`docs/manual/manual.html', and additionally at the Nix website at
-<http://nixos.org/>.
-
-
-Acknowledgments
-
-This product includes software developed by the OpenSSL Project for
-use in the OpenSSL Toolkit (http://www.OpenSSL.org/).
@@ -0,0 +1,22 @@
+Nix, the purely functional package manager
+------------------------------------------
+
+Nix is a new take on package management that is fairly unique. Because of it's
+purity aspects, a lot of issues found in traditional package managers don't
+appear with Nix.
+
+To find out more about the tool, usage and installation instructions, please
+read the manual, which is available on the Nix website at
+<http://nixos.org/nix/manual>.
+
+## Contributing
+
+Take a look at the [Hacking Section](http://nixos.org/nix/manual/#chap-hacking)
+of the manual. It helps you to get started with building Nix from source.
+
+## License
+
+Nix is released under the LGPL v2.1
+
+This product includes software developed by the OpenSSL Project for
+use in the [OpenSSL Toolkit](http://www.OpenSSL.org/).
@@ -1,169 +0,0 @@
-with import <nix-make/lib>;
-with pkgs;
-
-rec {
-
-  bin2c = link {
-    objects = [ (compileC { main = ./src/bin2c/bin2c.c; }) ];
-    programName = "bin2c";
-  };
-
-  bsdiff = link {
-    objects = [ (compileC { main = ./src/bsdiff-4.3/bsdiff.c; buildInputs = [ pkgs.bzip2 ]; }) ];
-    programName = "bsdiff";
-    buildInputs = [ pkgs.bzip2 ];
-    flags = "-lbz2";
-  };
-
-  bspatch = link {
-    objects = [ (compileC { main = ./src/bsdiff-4.3/bspatch.c; buildInputs = [ pkgs.bzip2 ]; }) ];
-    programName = "bspatch";
-    buildInputs = [ pkgs.bzip2 ];
-    flags = "-lbz2";
-  };
-
-  libformat = makeLibrary {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src ];
-      })
-      [ ./src/boost/format/format_implementation.cc
-        ./src/boost/format/free_funcs.cc
-        ./src/boost/format/parsing.cc
-      ];
-    libraryName = "format";
-  };
-
-  libutil = makeLibrary {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/libutil ./src ./. ];
-        buildInputs = [ pkgs.openssl ];
-      })
-      [ ./src/libutil/util.cc
-        ./src/libutil/hash.cc
-        ./src/libutil/serialise.cc
-        ./src/libutil/archive.cc
-        ./src/libutil/xml-writer.cc
-        ./src/libutil/immutable.cc
-      ];
-    libraryName = "util";
-  };
-
-  libstore = makeLibrary {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/libstore ./src/libutil ./src ./. ];
-        buildInputs = [ pkgs.sqlite ];
-        cFlags = "-DNIX_STORE_DIR=\"/nix/store\" -DNIX_DATA_DIR=\"/home/eelco/Dev/nix/inst/share\" -DNIX_STATE_DIR=\"/nix/var/nix\" -DNIX_LOG_DIR=\"/foo\" -DNIX_CONF_DIR=\"/foo\" -DNIX_LIBEXEC_DIR=\"/foo\" -DNIX_BIN_DIR=\"/home/eelco/Dev/nix/inst/bin\"";
-      })
-      [ ./src/libstore/store-api.cc
-        ./src/libstore/local-store.cc
-        ./src/libstore/remote-store.cc
-        ./src/libstore/derivations.cc
-        ./src/libstore/build.cc
-        ./src/libstore/misc.cc
-        ./src/libstore/globals.cc
-        ./src/libstore/references.cc
-        ./src/libstore/pathlocks.cc
-        ./src/libstore/gc.cc
-        ./src/libstore/optimise-store.cc
-      ];
-    libraryName = "store";
-  };
-
-  libmain = makeLibrary {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/libmain ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/libmain/shared.cc ];
-    libraryName = "main";
-  };
-
-  nix_hash = link {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/nix-hash ./src/libmain ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/nix-hash/nix-hash.cc
-      ];
-    libraries = [ libformat libutil libstore libmain ];
-    buildInputs = [ pkgs.openssl pkgs.sqlite ];
-    flags = "-lssl -lsqlite3 -lstdc++";
-    programName = "nix-hash";
-  };
-
-  nix_store = link {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/nix-store ./src/libmain ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/nix-store/nix-store.cc
-        ./src/nix-store/dotgraph.cc
-        ./src/nix-store/xmlgraph.cc
-      ];
-    libraries = [ libformat libutil libstore libmain ];
-    buildInputs = [ pkgs.openssl pkgs.sqlite ];
-    flags = "-lssl -lsqlite3 -lstdc++";
-    programName = "nix-store";
-  };
-
-  libexpr = makeLibrary {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/libexpr ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/libexpr/nixexpr.cc
-        ./src/libexpr/eval.cc
-        ./src/libexpr/primops.cc
-        ./src/libexpr/lexer-tab.cc
-        ./src/libexpr/parser-tab.cc
-        ./src/libexpr/get-drvs.cc
-        ./src/libexpr/attr-path.cc
-        ./src/libexpr/value-to-xml.cc
-        ./src/libexpr/common-opts.cc
-        ./src/libexpr/names.cc
-      ];
-    libraryName = "expr";
-  };
-
-  nix_instantiate = link {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/nix-instantiate ./src/libexpr ./src/libmain ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/nix-instantiate/nix-instantiate.cc ];
-    libraries = [ libformat libutil libstore libmain libexpr ];
-    buildInputs = [ pkgs.openssl pkgs.sqlite ];
-    flags = "-lssl -lsqlite3 -lstdc++";
-    programName = "nix-instantiate";
-  };
-
-  nix_env = link {
-    objects =
-      map (fn: compileC {
-        main = fn;
-        localIncludePath = [ ./src/nix-env ./src/libexpr ./src/libmain ./src/libstore ./src/libutil ./src ./. ];
-      })
-      [ ./src/nix-env/nix-env.cc
-        ./src/nix-env/profiles.cc
-        ./src/nix-env/user-env.cc
-      ];
-    libraries = [ libformat libutil libstore libmain libexpr ];
-    buildInputs = [ pkgs.openssl pkgs.sqlite ];
-    flags = "-lssl -lsqlite3 -lstdc++";
-    programName = "nix-env";
-  };
-
-  all = [ bsdiff bspatch nix_hash nix_store nix_instantiate nix_env ];
-
-}
@@ -1,5 +1,5 @@
 AC_INIT(nix, m4_esyscmd([bash -c "echo -n $(cat ./version)$VERSION_SUFFIX"]))
-AC_CONFIG_SRCDIR(README)
+AC_CONFIG_SRCDIR(README.md)
 AC_CONFIG_AUX_DIR(config)

 AC_PROG_SED
@@ -16,12 +16,14 @@ AC_ARG_WITH(system, AC_HELP_STRING([--with-system=SYSTEM],
        machine_name="i686";;
     amd64)
        machine_name="x86_64";;
+     armv6|armv7)
+        machine_name="${host_cpu}l";;
     *)
        machine_name="$host_cpu";;
   esac

   case "$host_os" in
-     linux-gnu*)
+     linux-gnu*|linux-musl*)
        # For backward compatibility, strip the `-gnu' part.
        system="$machine_name-linux";;
     *)
@@ -48,16 +50,18 @@ test "$localstatedir" = '${prefix}/var' && localstatedir=/nix/var


 # Solaris-specific stuff.
+AC_STRUCT_DIRENT_D_TYPE
 if test "$sys_name" = sunos; then
    # Solaris requires -lsocket -lnsl for network functions
    LIBS="-lsocket -lnsl $LIBS"
 fi


-CFLAGS=${CFLAGS:--g -O3 -Wall}
-CXXFLAGS=${CXXFLAGS:--g -O3 -Wall}
+CFLAGS=
+CXXFLAGS=
 AC_PROG_CC
 AC_PROG_CXX
+AX_CXX_COMPILE_STDCXX_11


 # Use 64-bit file system calls so that we can support files > 2 GiB.
@@ -76,21 +80,7 @@ static char buf[1024];]],
 AC_LANG_POP(C++)


-# Check for chroot support (requires chroot() and bind mounts).
-AC_CHECK_FUNCS([chroot])
-AC_CHECK_FUNCS([unshare])
-AC_CHECK_FUNCS([statvfs])
-AC_CHECK_HEADERS([sched.h])
-AC_CHECK_HEADERS([sys/param.h])
-AC_CHECK_HEADERS([sys/mount.h], [], [],
-[#ifdef HAVE_SYS_PARAM_H
-# include <sys/param.h>
-# endif
-])
-
-
-# Check for vfork.
-#AC_FUNC_FORK()
+AC_CHECK_FUNCS([statvfs pipe2])


 # Check for lutimes, optionally used for changing the mtime of
@@ -98,10 +88,6 @@ AC_CHECK_HEADERS([sys/mount.h], [], [],
 AC_CHECK_FUNCS([lutimes])


-# Check for sched_setaffinity.
-AC_CHECK_FUNCS([sched_setaffinity])
-
-
 # Check whether the store optimiser can optimise symlinks.
 AC_MSG_CHECKING([whether it is possible to create a link to a symlink])
 ln -s bla tmp_link
@@ -120,26 +106,6 @@ AC_CHECK_HEADERS([locale])
 AC_LANG_POP(C++)


-# Check for <err.h>.
-AC_CHECK_HEADER([err.h], [], [bsddiff_compat_include="-Icompat-include"])
-AC_SUBST([bsddiff_compat_include])
-
-
-# Check whether we have the personality() syscall, which allows us to
-# do i686-linux builds on x86_64-linux machines.
-AC_CHECK_HEADERS([sys/personality.h])
-
-
-# Check for <linux/fs.h> (for immutable file support).
-AC_CHECK_HEADERS([linux/fs.h])
-
-
-# Check for tr1/unordered_set.
-AC_LANG_PUSH(C++)
-AC_CHECK_HEADERS([tr1/unordered_set])
-AC_LANG_POP(C++)
-
-
 AC_DEFUN([NEED_PROG],
 [
 AC_PATH_PROG($1, $2)
@@ -153,7 +119,6 @@ NEED_PROG(bash, bash)
 NEED_PROG(patch, patch)
 AC_PATH_PROG(xmllint, xmllint, false)
 AC_PATH_PROG(xsltproc, xsltproc, false)
-AC_PATH_PROG(w3m, w3m, false)
 AC_PATH_PROG(flex, flex, false)
 AC_PATH_PROG(bison, bison, false)
 NEED_PROG(perl, perl)
@@ -163,7 +128,6 @@ NEED_PROG(bzip2, bzip2)
 NEED_PROG(gzip, gzip)
 NEED_PROG(xz, xz)
 AC_PATH_PROG(dot, dot)
-AC_PATH_PROG(dblatex, dblatex)
 AC_PATH_PROG(pv, pv, pv)


@@ -192,33 +156,14 @@ AC_ARG_WITH(coreutils-bin, AC_HELP_STRING([--with-coreutils-bin=PATH],
 AC_SUBST(coreutils)


-AC_ARG_WITH(docbook-rng, AC_HELP_STRING([--with-docbook-rng=PATH],
-  [path of the DocBook RelaxNG schema]),
-  docbookrng=$withval, docbookrng=/docbook-rng-missing)
-AC_SUBST(docbookrng)
-
-AC_ARG_WITH(docbook-xsl, AC_HELP_STRING([--with-docbook-xsl=PATH],
-  [path of the DocBook XSL stylesheets]),
-  docbookxsl=$withval, docbookxsl=/docbook-xsl-missing)
-AC_SUBST(docbookxsl)
-
-
 AC_ARG_WITH(store-dir, AC_HELP_STRING([--with-store-dir=PATH],
  [path of the Nix store (defaults to /nix/store)]),
  storedir=$withval, storedir='/nix/store')
 AC_SUBST(storedir)


-# Look for OpenSSL, an optional dependency.
-AC_PATH_PROG(openssl, openssl, openssl) # if not found, call openssl in $PATH
-AC_SUBST(openssl)
-AC_DEFINE_UNQUOTED(OPENSSL_PATH, ["$openssl"], [Path of the OpenSSL binary])
-
-PKG_CHECK_MODULES([OPENSSL], [libcrypto],
-  [AC_DEFINE([HAVE_OPENSSL], [1], [Whether to use OpenSSL.])
-   CXXFLAGS="$OPENSSL_CFLAGS $CXXFLAGS"
-   have_openssl=1], [have_openssl=])
-AC_SUBST(HAVE_OPENSSL, [$have_openssl])
+# Look for OpenSSL, a required dependency.
+PKG_CHECK_MODULES([OPENSSL], [libcrypto], [CXXFLAGS="$OPENSSL_CFLAGS $CXXFLAGS"])


 # Look for libbz2, a required dependency.
@@ -232,6 +177,31 @@ AC_CHECK_HEADERS([bzlib.h], [true],
 PKG_CHECK_MODULES([SQLITE3], [sqlite3 >= 3.6.19], [CXXFLAGS="$SQLITE3_CFLAGS $CXXFLAGS"])


+# Look for libcurl, a required dependency.
+PKG_CHECK_MODULES([LIBCURL], [libcurl], [CXXFLAGS="$LIBCURL_CFLAGS $CXXFLAGS"])
+
+
+# Look for libsodium, an optional dependency.
+PKG_CHECK_MODULES([SODIUM], [libsodium],
+  [AC_DEFINE([HAVE_SODIUM], [1], [Whether to use libsodium for cryptography.])
+   CXXFLAGS="$SODIUM_CFLAGS $CXXFLAGS"
+   have_sodium=1], [have_sodium=])
+AC_SUBST(HAVE_SODIUM, [$have_sodium])
+
+
+# Look for liblzma, a required dependency.
+PKG_CHECK_MODULES([LIBLZMA], [liblzma], [CXXFLAGS="$LIBLZMA_CFLAGS $CXXFLAGS"])
+
+
+# Look for aws-cpp-sdk-s3.
+AC_LANG_PUSH(C++)
+AC_CHECK_HEADERS([aws/s3/S3Client.h],
+  [AC_DEFINE([ENABLE_S3], [1], [Whether to enable S3 support via aws-cpp-sdk-s3.])
+  enable_s3=1], [enable_s3=])
+AC_SUBST(ENABLE_S3, [$enable_s3])
+AC_LANG_POP(C++)
+
+
 # Whether to use the Boehm garbage collector.
 AC_ARG_ENABLE(gc, AC_HELP_STRING([--enable-gc],
  [enable garbage collection in the Nix expression evaluator (requires Boehm GC) [default=no]]),
@@ -243,7 +213,7 @@ if test "$gc" = yes; then
 fi


-# Check for the required Perl dependencies (DBI, DBD::SQLite and WWW::Curl).
+# Check for the required Perl dependencies (DBI, DBD::SQLite).
 perlFlags="-I$perllibdir"

 AC_ARG_WITH(dbi, AC_HELP_STRING([--with-dbi=PATH],
@@ -254,10 +224,6 @@ AC_ARG_WITH(dbd-sqlite, AC_HELP_STRING([--with-dbd-sqlite=PATH],
  [prefix of the Perl DBD::SQLite library]),
  perlFlags="$perlFlags -I$withval")

-AC_ARG_WITH(www-curl, AC_HELP_STRING([--with-www-curl=PATH],
-  [prefix of the Perl WWW::Curl library]),
-  perlFlags="$perlFlags -I$withval")
-
 AC_MSG_CHECKING([whether DBD::SQLite works])
 if ! $perl $perlFlags -e 'use DBI; use DBD::SQLite;' 2>&5; then
    AC_MSG_RESULT(no)
@@ -265,13 +231,6 @@ if ! $perl $perlFlags -e 'use DBI; use DBD::SQLite;' 2>&5; then
 fi
 AC_MSG_RESULT(yes)

-AC_MSG_CHECKING([whether WWW::Curl works])
-if ! $perl $perlFlags -e 'use WWW::Curl;' 2>&5; then
-    AC_MSG_RESULT(no)
-    AC_MSG_FAILURE([The Perl module WWW::Curl is missing.])
-fi
-AC_MSG_RESULT(yes)
-
 AC_SUBST(perlFlags)


@@ -294,6 +253,13 @@ AC_ARG_ENABLE(init-state, AC_HELP_STRING([--disable-init-state],
 #AM_CONDITIONAL(INIT_STATE, test "$init_state" = "yes")


+# documentation generation switch
+AC_ARG_ENABLE(doc-gen, AC_HELP_STRING([--disable-doc-gen],
+  [disable documentation generation]),
+  doc_generate=$enableval, doc_generate=yes)
+AC_SUBST(doc_generate)
+
+
 # Setuid installations.
 AC_CHECK_FUNCS([setresuid setreuid lchown])

@@ -334,6 +300,8 @@ for name in $ac_subst_vars; do
    declare $name="$(eval echo "${!name}")"
 done

+rm -f Makefile.config
+
 AC_CONFIG_HEADER([config.h])
 AC_CONFIG_FILES([])
 AC_OUTPUT
@@ -5,10 +5,9 @@ with import <nix/config.nix>;
 derivation {
  name = "user-environment";
  system = builtins.currentSystem;
-  builder = perl;
-  args = [ "-w" ./buildenv.pl ];
+  builder = nixLibexecDir + "/nix/buildenv";

-  manifest = manifest;
+  inherit manifest;

  # !!! grmbl, need structured data for passing this in a clean way.
  derivations =
@@ -23,6 +22,23 @@ derivation {
  # network traffic, so don't do that.
  preferLocalBuild = true;

-  # Don't build in a chroot because Nix's dependencies may not be there.
-  __noChroot = true;
+  # Also don't bother substituting.
+  allowSubstitutes = false;
+
+  __sandboxProfile = ''
+    (allow sysctl-read)
+    (allow file-read*
+           (literal "/usr/lib/libSystem.dylib")
+           (literal "/usr/lib/libSystem.B.dylib")
+           (literal "/usr/lib/libobjc.A.dylib")
+           (literal "/usr/lib/libobjc.dylib")
+           (literal "/usr/lib/libauto.dylib")
+           (literal "/usr/lib/libc++abi.dylib")
+           (literal "/usr/lib/libc++.1.dylib")
+           (literal "/usr/lib/libDiagnosticMessagesClient.dylib")
+           (subpath "/usr/lib/system")
+           (subpath "/dev"))
+  '';
+
+  inherit chrootDeps;
 }
@@ -1,168 +0,0 @@
-use strict;
-use Cwd;
-use IO::Handle;
-
-STDOUT->autoflush(1);
-
-my $out = $ENV{"out"};
-mkdir "$out", 0755 || die "error creating $out";
-
-
-my $symlinks = 0;
-
-my %priorities;
-
-
-# For each activated package, create symlinks.
-
-sub createLinks {
-    my $srcDir = shift;
-    my $dstDir = shift;
-    my $priority = shift;
-
-    my @srcFiles = glob("$srcDir/*");
-
-    foreach my $srcFile (@srcFiles) {
-        my $baseName = $srcFile;
-        $baseName =~ s/^.*\///g; # strip directory
-        my $dstFile = "$dstDir/$baseName";
-
-        # The files below are special-cased so that they don't show up
-        # in user profiles, either because they are useless, or
-        # because they would cause pointless collisions (e.g., each
-        # Python package brings its own
-        # `$out/lib/pythonX.Y/site-packages/easy-install.pth'.)
-        # Urgh, hacky...
-        if ($srcFile =~ /\/propagated-build-inputs$/ ||
-            $srcFile =~ /\/nix-support$/ ||
-            $srcFile =~ /\/perllocal.pod$/ ||
-            $srcFile =~ /\/info\/dir$/ ||
-            $srcFile =~ /\/log$/)
-        {
-            # Do nothing.
-        }
-
-        elsif (-d $srcFile) {
-
-            lstat $dstFile;
-
-            if (-d _) {
-                createLinks($srcFile, $dstFile, $priority);
-            }
-
-            elsif (-l _) {
-                my $target = readlink $dstFile or die;
-                if (!-d $target) {
-                    die "collision between directory `$srcFile' and non-directory `$target'";
-                }
-                unlink $dstFile or die "error unlinking `$dstFile': $!";
-                mkdir $dstFile, 0755 ||
-                    die "error creating directory `$dstFile': $!";
-                createLinks($target, $dstFile, $priorities{$dstFile});
-                createLinks($srcFile, $dstFile, $priority);
-            }
-
-            else {
-                symlink($srcFile, $dstFile) ||
-                    die "error creating link `$dstFile': $!";
-                $priorities{$dstFile} = $priority;
-                $symlinks++;
-            }
-        }
-
-        else {
-
-            if (-l $dstFile) {
-                my $target = readlink $dstFile;
-                my $prevPriority = $priorities{$dstFile};
-                die ( "collision between `$srcFile' and `$target'; "
-                    . "use `nix-env --set-flag "
-                    . "priority NUMBER PKGNAME' to change the priority of "
-                    . "one of the conflicting packages\n" )
-                    if $prevPriority == $priority;
-                next if $prevPriority < $priority;
-                unlink $dstFile or die;
-            }
-
-            symlink($srcFile, $dstFile) ||
-                die "error creating link `$dstFile': $!";
-            $priorities{$dstFile} = $priority;
-            $symlinks++;
-        }
-    }
-}
-
-
-my %done;
-my %postponed;
-
-sub addPkg;
-sub addPkg {
-    my $pkgDir = shift;
-    my $priority = shift;
-
-    return if (defined $done{$pkgDir});
-    $done{$pkgDir} = 1;
-
-#    print "symlinking $pkgDir\n";
-    createLinks("$pkgDir", "$out", $priority);
-
-    my $propagatedFN = "$pkgDir/nix-support/propagated-user-env-packages";
-    if (-e $propagatedFN) {
-        open PROP, "<$propagatedFN" or die;
-        my $propagated = <PROP>;
-        close PROP;
-        my @propagated = split ' ', $propagated;
-        foreach my $p (@propagated) {
-            $postponed{$p} = 1 unless defined $done{$p};
-        }
-    }
-}
-
-
-# Convert the stuff we get from the environment back into a coherent
-# data type.
-my @pkgs;
-my @derivations = split ' ', $ENV{"derivations"};
-while (scalar @derivations) {
-    my $active = shift @derivations;
-    my $priority = shift @derivations;
-    my $outputs = shift @derivations;
-    for (my $n = 0; $n < $outputs; $n++) {
-        my $path = shift @derivations;
-        push @pkgs,
-            { path => $path
-            , active => $active ne "false"
-            , priority => int($priority) };
-    }
-}
-
-
-# Symlink to the packages that have been installed explicitly by the
-# user.  Process in priority order to reduce unnecessary
-# symlink/unlink steps.
-@pkgs = sort { $a->{priority} <=> $b->{priority} || $a->{path} cmp $b->{path} } @pkgs;
-foreach my $pkg (@pkgs) {
-    #print $pkg, " ", $pkgs{$pkg}->{priority}, "\n";
-    addPkg($pkg->{path}, $pkg->{priority}) if $pkg->{active};
-}
-
-
-# Symlink to the packages that have been "propagated" by packages
-# installed by the user (i.e., package X declares that it want Y
-# installed as well).  We do these later because they have a lower
-# priority in case of collisions.
-my $priorityCounter = 1000; # don't care about collisions
-while (scalar(keys %postponed) > 0) {
-    my @pkgDirs = keys %postponed;
-    %postponed = ();
-    foreach my $pkgDir (sort @pkgDirs) {
-        addPkg($pkgDir, $priorityCounter++);
-    }
-}
-
-
-print STDERR "created $symlinks symlinks in user environment\n";
-
-
-symlink($ENV{"manifest"}, "$out/manifest.nix") or die "cannot create manifest";
@@ -2,8 +2,7 @@ let
  fromEnv = var: def:
    let val = builtins.getEnv var; in
    if val != "" then val else def;
-in {
-  perl = "@perl@";
+in rec {
  shell = "@bash@";
  coreutils = "@coreutils@";
  bzip2 = "@bzip2@";
@@ -12,6 +11,16 @@ in {
  tar = "@tar@";
  tarFlags = "@tarFlags@";
  tr = "@tr@";
-  curl = "@curl@";
  nixBinDir = fromEnv "NIX_BIN_DIR" "@bindir@";
+  nixPrefix = "@prefix@";
+  nixLibexecDir = fromEnv "NIX_LIBEXEC_DIR" "@libexecdir@";
+
+  # If Nix is installed in the Nix store, then automatically add it as
+  # a dependency to the core packages. This ensures that they work
+  # properly in a chroot.
+  chrootDeps =
+    if dirOf nixPrefix == builtins.storeDir then
+      [ (builtins.storePath nixPrefix) ]
+    else
+      [ ];
 }
@@ -1,37 +1,39 @@
-with import <nix/config.nix>;
-
-{system ? builtins.currentSystem, url, outputHash ? "", outputHashAlgo ? "", md5 ? "", sha1 ? "", sha256 ? "", executable ? false}:
+{ system ? builtins.currentSystem
+, url
+, outputHash ? ""
+, outputHashAlgo ? ""
+, md5 ? "", sha1 ? "", sha256 ? ""
+, executable ? false
+, unpack ? false
+, name ? baseNameOf (toString url)
+}:

 assert (outputHash != "" && outputHashAlgo != "")
    || md5 != "" || sha1 != "" || sha256 != "";

-let
-
-  builder = builtins.toFile "fetchurl.sh"
-    (''
-      echo "downloading $url into $out"
-      ${curl} --fail --location --max-redirs 20 --insecure "$url" > "$out"
-    '' + (if executable then "${coreutils}/chmod +x $out" else ""));
-
-in
-    
 derivation {
-  name = baseNameOf (toString url);
-  builder = shell;
-  args = [ "-e" builder ];
+  builder = "builtin:fetchurl";

  # New-style output content requirements.
  outputHashAlgo = if outputHashAlgo != "" then outputHashAlgo else
      if sha256 != "" then "sha256" else if sha1 != "" then "sha1" else "md5";
  outputHash = if outputHash != "" then outputHash else
      if sha256 != "" then sha256 else if sha1 != "" then sha1 else md5;
-  outputHashMode = if executable then "recursive" else "flat";
-  
-  inherit system url;
+  outputHashMode = if unpack || executable then "recursive" else "flat";
+
+  inherit name system url executable unpack;

  # No need to double the amount of network traffic
  preferLocalBuild = true;

-  # Don't build in a chroot because Nix's dependencies may not be there.
-  __noChroot = true;
+  impureEnvVars = [
+    # We borrow these environment variables from the caller to allow
+    # easy proxy configuration.  This is impure, but a fixed-output
+    # derivation like fetchurl is allowed to do so since its result is
+    # by definition pure.
+    "http_proxy" "https_proxy" "ftp_proxy" "all_proxy" "no_proxy"
+  ];
+
+  # To make "nix-prefetch-url" work.
+  urls = [ url ];
 }
@@ -1,10 +1,10 @@
-attrs @ { drvPath, outputs, ... }:
+attrs @ { drvPath, outputs, name, ... }:

 let

  commonAttrs = (builtins.listToAttrs outputsList) //
    { all = map (x: x.value) outputsList;
-      inherit drvPath;
+      inherit drvPath name;
      type = "derivation";
    };

@@ -1,4 +1,4 @@
-corepkgs_FILES = nar.nix buildenv.nix buildenv.pl unpack-channel.nix derivation.nix fetchurl.nix imported-drv-to-derivation.nix
+corepkgs_FILES = buildenv.nix unpack-channel.nix derivation.nix fetchurl.nix imported-drv-to-derivation.nix

 $(foreach file,config.nix $(corepkgs_FILES),$(eval $(call install-data-in,$(d)/$(file),$(datadir)/nix/corepkgs)))

@@ -1,49 +0,0 @@
-with import <nix/config.nix>;
-
-let
-
-  builder = builtins.toFile "nar.sh"
-    ''
-      export PATH=${nixBinDir}:${coreutils}
-
-      if [ $compressionType = xz ]; then
-        ext=.xz
-        compressor="| ${xz} -7"
-      elif [ $compressionType = bzip2 ]; then
-        ext=.bz2
-        compressor="| ${bzip2}"
-      else
-        ext=
-        compressor=
-      fi
-
-      echo "packing ‘$storePath’..."
-      mkdir $out
-      dst=$out/tmp.nar$ext
-
-      set -o pipefail
-      eval "nix-store --dump \"$storePath\" $compressor > $dst"
-
-      hash=$(nix-hash --flat --type $hashAlgo --base32 $dst)
-      echo -n $hash > $out/nar-compressed-hash
-
-      mv $dst $out/$hash.nar$ext
-    '';
-
-in
-
-{ storePath, hashAlgo, compressionType }:
-
-derivation {
-  name = "nar";
-  system = builtins.currentSystem;
-  builder = shell;
-  args = [ "-e" builder ];
-  inherit storePath hashAlgo compressionType;
-
-  # Don't build in a chroot because Nix's dependencies may not be there.
-  __noChroot = true;
-
-  # Remote machines may not have ${nixBinDir} or ${coreutils} in the same prefixes
-  preferLocalBuild = true;
-}
@@ -37,6 +37,5 @@ derivation {
  # No point in doing this remotely.
  preferLocalBuild = true;

-  # Don't build in a chroot because Nix's dependencies may not be there.
-  __noChroot = true;
+  inherit chrootDeps;
 }
@@ -1,17 +0,0 @@
-#! /bin/sh
-if [ -e tests/test-tmp ]; then
-    chmod -R u+w tests/test-tmp
-    rm -rf tests/test-tmp
-fi
-
-s=$(type -p nix-shell)
-exec $s release.nix -A tarball --command "
-    export NIX_REMOTE=daemon
-    export NIX_PATH='$NIX_PATH'
-    export NIX_BUILD_SHELL=$(type -p bash)
-    export c=\$configureFlags
-    exec $s release.nix -A build.x86_64-linux --exclude tarball --command '
-        configureFlags+=\" \$c --prefix=$(pwd)/inst --sysconfdir=$(pwd)/inst/etc\"
-        return
-    '" \
-    "$@"
@@ -0,0 +1,10 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0">
+
+<title>Advanced Topics</title>
+
+<xi:include href="distributed-builds.xml" />
+
+</part>
@@ -1,17 +1,19 @@
 <chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id='chap-distributed-builds'>
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='chap-distributed-builds'>

-<title>Setting Up Distributed Builds</title>
+<title>Distributed Builds</title>

-<para>Nix supports distributed builds: a local Nix installation can
+<para>Nix supports distributed builds, where a local Nix installation can
 forward Nix builds to other machines over the network.  This allows
 multiple builds to be performed in parallel (thus improving
 performance) and allows Nix to perform multi-platform builds in a
 semi-transparent way.  For instance, if you perform a build for a
-<literal>powerpc-darwin</literal> on an <literal>i686-linux</literal>
+<literal>x86_64-darwin</literal> on an <literal>i686-linux</literal>
 machine, Nix can automatically forward the build to a
-<literal>powerpc-darwin</literal> machine, if available.</para>
+<literal>x86_64-darwin</literal> machine, if available.</para>

 <para>You can enable distributed builds by setting the environment
 variable <envar>NIX_BUILD_HOOK</envar> to point to a program that Nix
@@ -28,7 +30,7 @@ variable</link>.</para>
 <example xml:id='ex-remote-systems'><title>Remote machine configuration:
 <filename>remote-systems.conf</filename></title>
 <programlisting>
-nix@mcflurry.labs.cs.uu.nl  powerpc-darwin  /home/nix/.ssh/id_quarterpounder_auto  2
+nix@mcflurry.labs.cs.uu.nl  x86_64-darwin   /home/nix/.ssh/id_quarterpounder_auto  2
 nix@scratchy.labs.cs.uu.nl  i686-linux      /home/nix/.ssh/id_scratchy_auto        8 1 kvm
 nix@itchy.labs.cs.uu.nl     i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2
 nix@poochie.labs.cs.uu.nl   i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2 kvm perf
@@ -42,13 +44,14 @@ outputs and perform the remote build.  To use it, you should set
 <envar>NIX_BUILD_HOOK</envar> to
 <filename><replaceable>prefix</replaceable>/libexec/nix/build-remote.pl</filename>.
 You should also define a list of available build machines and point
-the environment variable <envar>NIX_REMOTE_SYSTEMS</envar> to it.  An
+the environment variable <envar>NIX_REMOTE_SYSTEMS</envar> to
+it. <envar>NIX_REMOTE_SYSTEMS</envar> must be an absolute path. An
 example configuration is shown in <xref linkend='ex-remote-systems'
 />.  Each line in the file specifies a machine, with the following
 bits of information:

 <orderedlist>
-  
+
  <listitem><para>The name of the remote machine, with optionally the
  user under which the remote build should be performed.  This is
  actually passed as an argument to <command>ssh</command>, so it can
@@ -56,7 +59,7 @@ bits of information:
  <filename>~/.ssh/config</filename>.</para></listitem>

  <listitem><para>A comma-separated list of Nix platform type
-  identifiers, such as <literal>powerpc-darwin</literal>.  It is
+  identifiers, such as <literal>x86_64-darwin</literal>.  It is
  possible for a machine to support multiple platform types, e.g.,
  <literal>i686-linux,x86_64-linux</literal>.</para></listitem>

@@ -80,9 +83,9 @@ bits of information:
  <filename>build-remote.pl</filename> will only perform the
  derivation on a machine that has the specified features.  For
  instance, the attribute
-  
+
 <programlisting>
-requiredSystemFeatures = [ "kvm" ];  
+requiredSystemFeatures = [ "kvm" ];
 </programlisting>

  will cause the build to be performed on a machine that has the
@@ -109,5 +112,5 @@ load on the remote machine, so if you have multiple instances of Nix
 running, they should use the same <envar>NIX_CURRENT_LOAD</envar>
 file.  Maybe in the future <filename>build-remote.pl</filename> will
 look at the actual remote load.</para>
-  
+
 </chapter>
@@ -1,39 +0,0 @@
-<appendix xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink">
-
-<title>Bugs / To-Do</title>
-
-
-<itemizedlist>
-
-<listitem><para>The man-pages generated from the DocBook documentation
-are ugly.</para></listitem>
-
-<listitem><para>Generations properly form a tree.  E.g., if after
-switching to generation 39, we perform an installation action, a
-generation 43 is created which is a descendant of 39, not 42.  So a
-rollback from 43 ought to go back to 39.  This is not currently
-implemented; generations form a linear sequence.</para></listitem>
-
-<listitem><para>For security, <command>nix-push</command> manifests
-should be digitally signed, and <command>nix-pull</command> should
-verify the signatures.  The actual NAR archives in the cache do not
-need to be signed, since the manifest contains cryptographic hashes of
-these files (and <filename>fetchurl.nix</filename> checks
-them).</para></listitem>
-
-<listitem><para>It would be useful to have an option in
-<command>nix-env --delete-generations</command> to remove non-current
-generations older than a certain age.</para></listitem>
-
-<listitem><para>There should be a flexible way to change the user
-environment builder.  Currently, you have to replace
-<filename><replaceable>prefix</replaceable>/share/nix/corepkgs/buildenv/builder.pl</filename>,
-which is hard-coded into <command>nix-env</command>.  Also, the
-default builder should be more powerful.  For instance, there should
-be some way to specify priorities to resolve
-collisions.</para></listitem>
-
-</itemizedlist>
-
-</appendix>
@@ -0,0 +1,20 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='part-command-ref'>
+
+<title>Command Reference</title>
+
+<partintro>
+<para>This section lists commands and options that you can use when you
+work with Nix.</para>
+</partintro>
+
+<xi:include href="opt-common.xml" />
+<xi:include href="env-common.xml" />
+<xi:include href="main-commands.xml" />
+<xi:include href="utilities.xml" />
+<xi:include href="files.xml" />
+
+</part>
@@ -7,7 +7,7 @@
  <refentrytitle>nix.conf</refentrytitle>
  <manvolnum>5</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -18,7 +18,8 @@
 <refsection><title>Description</title>

 <para>A number of persistent settings of Nix are stored in the file
-<filename><replaceable>sysconfdir</replaceable>/nix/nix.conf</filename>.
+<filename><replaceable>sysconfdir</replaceable>/nix/nix.conf</filename> or
+<filename>$NIX_CONF_DIR/nix.conf</filename> if <envar>NIX_CONF_DIR</envar> is set.
 This file is a list of <literal><replaceable>name</replaceable> =
 <replaceable>value</replaceable></literal> pairs, one per line.
 Comments start with a <literal>#</literal> character.  Here is an example
@@ -66,7 +67,7 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
    <para>Keeping derivation around is useful for querying and
    traceability (e.g., it allows you to ask with what dependencies or
    options a store path was built), so by default this option is on.
-    Turn it off to safe a bit of disk space (or a lot if
+    Turn it off to save a bit of disk space (or a lot if
    <literal>gc-keep-outputs</literal> is also turned on).</para></listitem>

  </varlistentry>
@@ -224,48 +225,70 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
  </varlistentry>


-  <varlistentry><term><literal>build-use-chroot</literal></term>
+  <varlistentry><term><literal>build-use-sandbox</literal></term>

    <listitem><para>If set to <literal>true</literal>, builds will be
-    performed in a <emphasis>chroot environment</emphasis>, i.e., the
-    build will be isolated from the normal file system hierarchy and
-    will only see the Nix store, the temporary build directory, and
-    the directories configured with the <link
-    linkend='conf-build-chroot-dirs'><literal>build-chroot-dirs</literal>
-    option</link> (such as <filename>/proc</filename> and
-    <filename>/dev</filename>).  This is useful to prevent undeclared
-    dependencies on files in directories such as
-    <filename>/usr/bin</filename>.</para>
+    performed in a <emphasis>sandboxed environment</emphasis>, i.e.,
+    they’re isolated from the normal file system hierarchy and will
+    only see their dependencies in the Nix store, the temporary build
+    directory, private versions of <filename>/proc</filename>,
+    <filename>/dev</filename>, <filename>/dev/shm</filename> and
+    <filename>/dev/pts</filename> (on Linux), and the paths configured with the
+    <link linkend='conf-build-sandbox-paths'><literal>build-sandbox-paths</literal>
+    option</link>. This is useful to prevent undeclared dependencies
+    on files in directories such as <filename>/usr/bin</filename>. In
+    addition, on Linux, builds run in private PID, mount, network, IPC
+    and UTS namespaces to isolate them from other processes in the
+    system (except that fixed-output derivations do not run in private
+    network namespace to ensure they can access the network).</para>

-    <para>The use of a chroot requires that Nix is run as root (but
-    you can still use the <link
-    linkend='conf-build-users-group'>“build users” feature</link> to
-    perform builds under different users than root).  Currently,
-    chroot builds only work on Linux because Nix uses “bind mounts” to
-    make the Nix store and other directories available inside the
-    chroot.</para>
+    <para>Currently, sandboxing only work on Linux and Mac OS X. The use
+    of a sandbox requires that Nix is run as root (so you should use
+    the <link linkend='conf-build-users-group'>“build users”
+    feature</link> to perform the actual builds under different users
+    than root).</para>
+
+    <para>If this option is set to <literal>relaxed</literal>, then
+    fixed-output derivations and derivations that have the
+    <varname>__noChroot</varname> attribute set to
+    <literal>true</literal> do not run in sandboxes.</para>
+
+    <para>The default is <literal>false</literal>.</para>

    </listitem>

  </varlistentry>


-  <varlistentry xml:id="conf-build-chroot-dirs"><term><literal>build-chroot-dirs</literal></term>
+  <varlistentry xml:id="conf-build-sandbox-paths">
+    <term><literal>build-sandbox-paths</literal></term>

-    <listitem><para>When builds are performed in a chroot environment,
-    Nix will mount some directories from the normal file system
-    hierarchy inside the chroot.  These are the Nix store, the
-    temporary build directory (usually
-    <filename>/tmp/nix-build-<replaceable>drvname</replaceable>-<replaceable>number</replaceable></filename>),
-    the <literal>/proc</literal> filesystem, and the directories
-    listed here.  The default is <literal>/dev /dev/pts</literal>,
-    since these contain files needed by many builds (such as
-    <filename>/dev/null</filename>).  You can use the syntax
+    <listitem><para>A list of paths bind-mounted into Nix sandbox
+    environments. You can use the syntax
    <literal><replaceable>target</replaceable>=<replaceable>source</replaceable></literal>
-    to mount a path in a different location in the chroot; for
-    instance, <literal>/bin=/nix-bin</literal> will mount the
-    directory <literal>/nix-bin</literal> as <literal>/bin</literal>
-    inside the chroot.</para></listitem>
+    to mount a path in a different location in the sandbox; for
+    instance, <literal>/bin=/nix-bin</literal> will mount the path
+    <literal>/nix-bin</literal> as <literal>/bin</literal> inside the
+    sandbox. If <replaceable>source</replaceable> is followed by
+    <literal>?</literal>, then it is not an error if
+    <replaceable>source</replaceable> does not exist; for example,
+    <literal>/dev/nvidiactl?</literal> specifies that
+    <filename>/dev/nvidiactl</filename> will only be mounted in the
+    sandbox if it exists in the host filesystem.</para>
+
+    <para>Depending on how Nix was built, the default value for this option
+    may be empty or provide <filename>/bin/sh</filename> as a
+    bind-mount of <command>bash</command>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-build-extra-sandbox-paths">
+    <term><literal>build-extra-sandbox-paths</literal></term>
+
+    <listitem><para>A list of additional paths appended to
+    <option>build-sandbox-paths</option>. Useful if you want to extend
+    its default value.</para></listitem>

  </varlistentry>

@@ -289,21 +312,6 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
  </varlistentry>


-  <varlistentry><term><literal>build-cache-failures</literal></term>
-
-    <listitem><para>If set to <literal>true</literal>, Nix will
-    “cache” build failures, meaning that it will remember (in its
-    database) that a derivation previously failed.  If you then try to
-    build the derivation again, Nix will immediately fail rather than
-    perform the build again.  Failures in fixed-output derivations
-    (such as <function>fetchurl</function> calls) are never cached.
-    The “failed” status of a derivation can be cleared using
-    <command>nix-store --clear-failed-paths</command>.  By default,
-    failure caching is disabled.</para></listitem>
-
-  </varlistentry>
-
-
  <varlistentry><term><literal>build-keep-log</literal></term>

    <listitem><para>If set to <literal>true</literal> (the default),
@@ -340,7 +348,7 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>

    <listitem><para>A list of URLs of binary caches, separated by
    whitespace.  The default is
-    <literal>http://cache.nixos.org</literal>.</para></listitem>
+    <literal>https://cache.nixos.org</literal>.</para></listitem>

  </varlistentry>

@@ -384,24 +392,40 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
  </varlistentry>


-  <varlistentry><term><literal>binary-caches-parallel-connections</literal></term>
+  <varlistentry><term><literal>signed-binary-caches</literal></term>

-    <listitem><para>The maximum number of parallel HTTP connections
-    used by the binary cache substituter to get NAR info files.  This
-    number should be high to minimise latency.  It defaults to
-    150.</para></listitem>
+    <listitem><para>If set to <literal>*</literal>, Nix will only
+    download binaries if they are signed using one of the keys listed
+    in <option>binary-cache-public-keys</option>.</para></listitem>

  </varlistentry>


-  <varlistentry><term><literal>force-manifest</literal></term>
+  <varlistentry><term><literal>binary-cache-public-keys</literal></term>

-    <listitem><para>If this option is set to <literal>false</literal>
-    (default) and a Nix channel provides both a manifest and a binary
-    cache, only the binary cache will be used.  If set to
-    <literal>true</literal>, the manifest will be fetched as well.
-    This is useful if you want to use binary patches (which are
-    currently not supported by binary caches).</para></listitem>
+    <listitem><para>A whitespace-separated list of public keys
+    corresponding to the secret keys trusted to sign binary
+    caches. For example:
+    <literal>cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+    hydra.nixos.org-1:CNHJZBh9K4tP3EKF6FkkgeVYsS3ohTl+oS0Qa8bezVs=</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>binary-caches-parallel-connections</literal></term>
+
+    <listitem><para>The maximum number of parallel TCP connections
+    used to fetch files from binary caches and by other downloads. It
+    defaults to 25. 0 means no limit.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><literal>verify-https-binary-caches</literal></term>
+
+    <listitem><para>Whether HTTPS binary caches are required to have a
+    certificate that can be verified. Defaults to
+    <literal>true</literal>.</para></listitem>

  </varlistentry>

@@ -411,15 +435,15 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
    <listitem><para>This option specifies the canonical Nix system
    name of the current installation, such as
    <literal>i686-linux</literal> or
-    <literal>powerpc-darwin</literal>.  Nix can only build derivations
+    <literal>x86_64-darwin</literal>.  Nix can only build derivations
    whose <literal>system</literal> attribute equals the value
    specified here.  In general, it never makes sense to modify this
    value from its default, since you can use it to ‘lie’ about the
    platform you are building on (e.g., perform a Mac OS build on a
    Linux machine; the result would obviously be wrong).  It only
    makes sense if the Nix binaries can run on multiple platforms,
-    e.g., ‘universal binaries’ that run on <literal>powerpc-darwin</literal> and
-    <literal>i686-darwin</literal>.</para>
+    e.g., ‘universal binaries’ that run on <literal>x86_64-linux</literal> and
+    <literal>i686-linux</literal>.</para>

    <para>It defaults to the canonical Nix system name detected by
    <filename>configure</filename> at build time.</para></listitem>
@@ -465,6 +489,138 @@ flag, e.g. <literal>--option gc-keep-outputs false</literal>.</para>
  </varlistentry>


+  <varlistentry xml:id="conf-log-servers"><term><literal>log-servers</literal></term>
+
+    <listitem>
+
+      <para>A list of URL prefixes (such as
+      <literal>http://hydra.nixos.org/log</literal>) from which
+      <command>nix-store -l</command> will try to fetch build logs if
+      they’re not available locally.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-trusted-users"><term><literal>trusted-users</literal></term>
+
+    <listitem>
+
+      <para>A list of names of users (separated by whitespace) that
+      have additional rights when connecting to the Nix daemon, such
+      as the ability to specify additional binary caches, or to import
+      unsigned NARs. You can also specify groups by prefixing them
+      with <literal>@</literal>; for instance,
+      <literal>@wheel</literal> means all users in the
+      <literal>wheel</literal> group. The default is
+      <literal>root</literal>.</para>
+
+      <warning><para>The users listed here have the ability to
+      compromise the security of a multi-user Nix store. For instance,
+      they could install Trojan horses subsequently executed by other
+      users. So you should consider carefully whether to add users to
+      this list.</para></warning>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-allowed-users"><term><literal>allowed-users</literal></term>
+
+    <listitem>
+
+      <para>A list of names of users (separated by whitespace) that
+      are allowed to connect to the Nix daemon. As with the
+      <option>trusted-users</option> option, you can specify groups by
+      prefixing them with <literal>@</literal>. Also, you can allow
+      all users by specifying <literal>*</literal>. The default is
+      <literal>*</literal>.</para>
+
+      <para>Note that trusted users are always allowed to connect.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-restrict-eval"><term><literal>restrict-eval</literal></term>
+
+    <listitem>
+
+      <para>If set to <literal>true</literal>, the Nix evaluator will
+      not allow access to any files outside of the Nix search path (as
+      set via the <envar>NIX_PATH</envar> environment variable or the
+      <option>-I</option> option). The default is
+      <literal>false</literal>.</para>
+
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-pre-build-hook"><term><literal>pre-build-hook</literal></term>
+
+    <listitem>
+
+
+      <para>If set, the path to a program that can set extra
+      derivation-specific settings for this system. This is used for settings
+      that can't be captured by the derivation model itself and are too variable
+      between different versions of the same system to be hard-coded into nix.
+      </para>
+
+      <para>The hook is passed the derivation path and, if sandboxes are enabled,
+      the sandbox directory. It can then modify the sandbox and send a series of
+      commands to modify various settings to stdout. The currently recognized
+      commands are:</para>
+
+      <variablelist>
+        <varlistentry xml:id="extra-sandbox-paths">
+          <term><literal>extra-sandbox-paths</literal></term>
+
+          <listitem>
+
+            <para>Pass a list of files and directories to be included in the
+            sandbox for this build. One entry per line, terminated by an empty
+            line. Entries have the same format as
+            <literal>build-sandbox-paths</literal>.</para>
+
+          </listitem>
+
+        </varlistentry>
+      </variablelist>
+    </listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-build-repeat"><term><literal>build-repeat</literal></term>
+
+    <listitem><para>How many times to repeat builds to check whether
+    they are deterministic. The default value is 0. If the value is
+    non-zero, every build is repeated the specified number of
+    times. If the contents of any of the runs differs from the
+    previous ones, the build is rejected and the resulting store paths
+    are not registered as “valid” in Nix’s database.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="conf-sandbox-dev-shm-size"><term><literal>sandbox-dev-shm-size</literal></term>
+
+    <listitem><para>This option determines the maximum size of the
+    <literal>tmpfs</literal> filesystem mounted on
+    <filename>/dev/shm</filename> in Linux sandboxes. For the format,
+    see the description of the <option>size</option> option of
+    <literal>tmpfs</literal> in
+    <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>. The
+    default is <literal>50%</literal>.</para></listitem>
+
+  </varlistentry>
+
+
 </variablelist>

 </para>
@@ -1,16 +1,24 @@
-<section xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id="sec-common-env">
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-common-env">

-<title>Common environment variables</title>
+<title>Common Environment Variables</title>


 <para>Most Nix commands interpret the following environment variables:</para>

 <variablelist xml:id="env-common">

-  
-<varlistentry><term><envar>NIX_PATH</envar></term>
+<varlistentry><term><envar>IN_NIX_SHELL</envar></term>
+
+  <listitem><para>Indicator that tells if the current environment was set up by
+  <command>nix-shell</command>.</para></listitem>
+
+</varlistentry>
+
+<varlistentry xml:id="env-NIX_PATH"><term><envar>NIX_PATH</envar></term>

  <listitem>

@@ -26,7 +34,7 @@
    <filename>/home/eelco/Dev</filename> and
    <filename>/etc/nixos</filename>, in that order.  It is also
    possible to match paths against a prefix.  For example, the value
-    
+
    <screen>
 nixpkgs=/home/eelco/Dev/nixpkgs-branch:/etc/nixos</screen>

@@ -34,15 +42,27 @@ nixpkgs=/home/eelco/Dev/nixpkgs-branch:/etc/nixos</screen>
    <literal>&lt;nixpkgs/<replaceable>path</replaceable>></literal> in
    <filename>/home/eelco/Dev/nixpkgs-branch/<replaceable>path</replaceable></filename>
    and
-    <filename>/etc/nixos/nixpkgs/<replaceable>path</replaceable></filename>.
-    </para>
+    <filename>/etc/nixos/nixpkgs/<replaceable>path</replaceable></filename>.</para>

-    <para>The search path can be extended using the
-    <option>-I</option> option, which takes precedence over
+    <para>If a path in the Nix search path starts with
+    <literal>http://</literal> or <literal>https://</literal>, it is
+    interpreted as the URL of a tarball that will be downloaded and
+    unpacked to a temporary location. The tarball must consist of a
+    single top-level directory. For example, setting
+    <envar>NIX_PATH</envar> to
+
+    <screen>
+nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz</screen>
+
+    tells Nix to download the latest revision in the Nixpkgs/NixOS
+    14.12 channel.</para>
+
+    <para>The search path can be extended using the <option
+    linkend="opt-I">-I</option> option, which takes precedence over
    <envar>NIX_PATH</envar>.</para></listitem>

 </varlistentry>
-    
+

 <varlistentry><term><envar>NIX_IGNORE_SYMLINK_STORE</envar></term>

@@ -65,7 +85,7 @@ nixpkgs=/home/eelco/Dev/nixpkgs-branch:/etc/nixos</screen>
  you’re better off using <literal>bind</literal> mount points, e.g.,

  <screen>
-$ mkdir /nix   
+$ mkdir /nix
 $ mount -o bind /mnt/otherdisk/nix /nix</screen>

  Consult the <citerefentry><refentrytitle>mount</refentrytitle>
@@ -80,7 +100,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>

  <listitem><para>Overrides the location of the Nix store (default
  <filename><replaceable>prefix</replaceable>/store</filename>).</para></listitem>
-  
+
 </varlistentry>


@@ -89,7 +109,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
  <listitem><para>Overrides the location of the Nix static data
  directory (default
  <filename><replaceable>prefix</replaceable>/share</filename>).</para></listitem>
-  
+
 </varlistentry>


@@ -97,7 +117,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>

  <listitem><para>Overrides the location of the Nix log directory
  (default <filename><replaceable>prefix</replaceable>/log/nix</filename>).</para></listitem>
-  
+
 </varlistentry>


@@ -105,16 +125,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>

  <listitem><para>Overrides the location of the Nix state directory
  (default <filename><replaceable>prefix</replaceable>/var/nix</filename>).</para></listitem>
-  
-</varlistentry>

-
-<varlistentry><term><envar>NIX_DB_DIR</envar></term>
-
-  <listitem><para>Overrides the location of the Nix database (default
-  <filename><replaceable>$NIX_STATE_DIR</replaceable>/db</filename>, i.e.,
-  <filename><replaceable>prefix</replaceable>/var/nix/db</filename>).</para></listitem>
-  
 </varlistentry>


@@ -123,18 +134,9 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
  <listitem><para>Overrides the location of the Nix configuration
  directory (default
  <filename><replaceable>prefix</replaceable>/etc/nix</filename>).</para></listitem>
-  
-</varlistentry>
-
-
-<varlistentry><term><envar>NIX_LOG_TYPE</envar></term>
-
-  <listitem><para>Equivalent to the <link
-  linkend="opt-log-type"><option>--log-type</option>
-  option</link>.</para></listitem>

 </varlistentry>
-  
+

 <varlistentry><term><envar>TMPDIR</envar></term>

@@ -142,7 +144,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
  files.  In particular, this includes temporary build directories;
  these can take up substantial amounts of disk space.  The default is
  <filename>/tmp</filename>.</para></listitem>
-  
+
 </varlistentry>


@@ -240,7 +242,7 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>
      store derivation itself).</para></listitem>

    </varlistentry>
-  
+
    <varlistentry><term><filename>outputs</filename></term>

      <listitem><para>The set of store paths that are outputs of the
@@ -289,28 +291,6 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>

 </varlistentry>

-    
-<varlistentry xml:id="envar-other-stores"><term><envar>NIX_OTHER_STORES</envar></term>
-
-  <listitem><para>This variable contains the paths of remote Nix
-  installations from which packages can be copied, separated by colons.
-  <phrase condition="manual">See <xref linkend="sec-sharing-packages"
-  /> for details.</phrase>  Each path should be the
-  <filename>/nix</filename> directory of a remote Nix installation
-  (i.e., not the <filename>/nix/store</filename> directory).  The
-  paths are subject to globbing, so you can set it so something like
-  <literal>/var/run/nix/remote-stores/*/nix</literal> and mount
-  multiple remote filesystems in
-  <literal>/var/run/nix/remote-stores</literal>.</para>
-
-  <para>Note that if you’re building through the <link
-  linkend="sec-nix-daemon">Nix daemon</link>, the only setting for
-  this variable that matters is the one that the
-  <command>nix-daemon</command> process uses.  So if you want to
-  change it, you have to restart the daemon.</para></listitem>
-
-</varlistentry>
-

 <varlistentry><term><envar>NIX_SHOW_STATS</envar></term>

@@ -340,8 +320,8 @@ $ mount -o bind /mnt/otherdisk/nix /nix</screen>

 </varlistentry>

-    
+
 </variablelist>


-</section>
+</chapter>
@@ -0,0 +1,14 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='ch-files'>
+
+<title>Files</title>
+
+<para>This section lists configuration files that you can use when you
+work with Nix.</para>
+
+<xi:include href="conf-file.xml" />
+
+</chapter>
@@ -0,0 +1,17 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='ch-main-commands'>
+
+<title>Main Commands</title>
+
+<para>This section lists commands and options that you can use when you
+work with Nix.</para>
+
+<xi:include href="nix-env.xml" />
+<xi:include href="nix-build.xml" />
+<xi:include href="nix-shell.xml" />
+<xi:include href="nix-store.xml" />
+
+</chapter>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-build">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-build">

 <refmeta>
  <refentrytitle>nix-build</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -57,6 +58,13 @@ and so on).</para>
 <command>nix-build</command> will use <filename>default.nix</filename>
 in the current directory, if it exists.</para>

+<para>If an element of <replaceable>paths</replaceable> starts with
+<literal>http://</literal> or <literal>https://</literal>, it is
+interpreted as the URL of a tarball that will be downloaded and
+unpacked to a temporary location. The tarball must include a single
+top-level directory containing at least a file named
+<filename>default.nix</filename>.</para>
+
 <para><command>nix-build</command> is essentially a wrapper around
 <link
 linkend="sec-nix-instantiate"><command>nix-instantiate</command></link>
@@ -174,6 +182,15 @@ bar

 </para>

+<para>Build the GNU Hello package from the latest revision of the
+master branch of Nixpkgs:
+
+<screen>
+$ nix-build https://github.com/NixOS/nixpkgs/archive/master.tar.gz -A hello
+</screen>
+
+</para>
+
 </refsection>


@@ -0,0 +1,191 @@
+<refentry xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-channel">
+
+<refmeta>
+  <refentrytitle>nix-channel</refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo class="source">Nix</refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
+</refmeta>
+
+<refnamediv>
+  <refname>nix-channel</refname>
+  <refpurpose>manage Nix channels</refpurpose>
+</refnamediv>
+
+<refsynopsisdiv>
+  <cmdsynopsis>
+    <command>nix-channel</command>
+    <group choice='req'>
+      <arg choice='plain'><option>--add</option> <replaceable>url</replaceable> <arg choice='opt'><replaceable>name</replaceable></arg></arg>
+      <arg choice='plain'><option>--remove</option> <replaceable>name</replaceable></arg>
+      <arg choice='plain'><option>--list</option></arg>
+      <arg choice='plain'><option>--update</option> <arg rep='repeat'><replaceable>names</replaceable></arg></arg>
+      <arg choice='plain'><option>--rollback</option> <arg choice='opt'><replaceable>generation</replaceable></arg></arg>
+    </group>
+  </cmdsynopsis>
+</refsynopsisdiv>
+
+<refsection><title>Description</title>
+
+<para>A Nix channel is mechanism that allows you to automatically stay
+up-to-date with a set of pre-built Nix expressions.  A Nix channel is
+just a URL that points to a place containing both a set of Nix
+expressions and a pointer to a binary cache.  <phrase
+condition="manual">See also <xref linkend="sec-channels"
+/>.</phrase></para>
+
+<para>This command has the following operations:
+
+<variablelist>
+
+  <varlistentry><term><option>--add</option> <replaceable>url</replaceable> [<replaceable>name</replaceable>]</term>
+
+    <listitem><para>Adds a channel named
+    <replaceable>name</replaceable> with URL
+    <replaceable>url</replaceable> to the list of subscribed channels.
+    If <replaceable>name</replaceable> is omitted, it defaults to the
+    last component of <replaceable>url</replaceable>, with the
+    suffixes <literal>-stable</literal> or
+    <literal>-unstable</literal> removed.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--remove</option> <replaceable>name</replaceable></term>
+
+    <listitem><para>Removes the channel named
+    <replaceable>name</replaceable> from the list of subscribed
+    channels.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--list</option></term>
+
+    <listitem><para>Prints the names and URLs of all subscribed
+    channels on standard output.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--update</option> [<replaceable>names</replaceable>…]</term>
+
+    <listitem><para>Downloads the Nix expressions of all subscribed
+    channels (or only those included in
+    <replaceable>names</replaceable> if specified) and makes them the
+    default for <command>nix-env</command> operations (by symlinking
+    them from the directory
+    <filename>~/.nix-defexpr</filename>).</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--rollback</option> [<replaceable>generation</replaceable>]</term>
+
+    <listitem><para>Reverts the previous call to <command>nix-channel
+    --update</command>. Optionally, you can specify a specific channel
+    generation number to restore.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</para>
+
+<para>Note that <option>--add</option> does not automatically perform
+an update.</para>
+
+<para>The list of subscribed channels is stored in
+<filename>~/.nix-channels</filename>.</para>
+
+</refsection>
+
+<refsection><title>Examples</title>
+
+<para>To subscribe to the Nixpkgs channel and install the GNU Hello package:</para>
+
+<screen>
+$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable
+$ nix-channel --update
+$ nix-env -iA nixpkgs.hello</screen>
+
+<para>You can revert channel updates using <option>--rollback</option>:</para>
+
+<screen>
+$ nix-instantiate --eval -E '(import &lt;nixpkgs> {}).lib.nixpkgsVersion'
+"14.04.527.0e935f1"
+
+$ nix-channel --rollback
+switching from generation 483 to 482
+
+$ nix-instantiate --eval -E '(import &lt;nixpkgs> {}).lib.nixpkgsVersion'
+"14.04.526.dbadfad"
+</screen>
+
+</refsection>
+
+<refsection><title>Files</title>
+
+<variablelist>
+
+  <varlistentry><term><filename>/nix/var/nix/profiles/per-user/<replaceable>username</replaceable>/channels</filename></term>
+
+    <listitem><para><command>nix-channel</command> uses a
+    <command>nix-env</command> profile to keep track of previous
+    versions of the subscribed channels. Every time you run
+    <command>nix-channel --update</command>, a new channel generation
+    (that is, a symlink to the channel Nix expressions in the Nix store)
+    is created. This enables <command>nix-channel --rollback</command>
+    to revert to previous versions.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><filename>~/.nix-defexpr/channels</filename></term>
+
+    <listitem><para>This is a symlink to
+    <filename>/nix/var/nix/profiles/per-user/<replaceable>username</replaceable>/channels</filename>. It
+    ensures that <command>nix-env</command> can find your channels. In
+    a multi-user installation, you may also have
+    <filename>~/.nix-defexpr/channels_root</filename>, which links to
+    the channels of the root user.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</refsection>
+
+<refsection><title>Channel format</title>
+
+<para>A channel URL should point to a directory containing the
+following files:</para>
+
+<variablelist>
+
+  <varlistentry><term><filename>nixexprs.tar.xz</filename></term>
+
+    <listitem><para>A tarball containing Nix expressions and files
+    referenced by them (such as build scripts and patches). At
+    top-level, the tarball should contain a single directory. That
+    directory must contain a file <filename>default.nix</filename>
+    that serves as the channel’s “entry point”.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><filename>binary-cache-url</filename></term>
+
+    <listitem><para>A file containing the URL to a binary cache (such
+    as <uri>https://cache.nixos.org</uri>. Nix will automatically
+    check this cache for pre-built binaries, if the user has
+    sufficient rights to add binary caches. For instance, in a
+    multi-user Nix setup, the binary caches provided by the channels
+    of the root user are used automatically, but caches corresponding
+    to the channels of non-root users are ignored.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</refsection>
+
+</refentry>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-collect-garbage">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-collect-garbage">
  
 <refmeta>
  <refentrytitle>nix-collect-garbage</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -27,6 +28,7 @@
      <arg choice='plain'><option>--print-dead</option></arg>
      <arg choice='plain'><option>--delete</option></arg>
    </group>
+    <arg><option>--max-freed</option> <replaceable>bytes</replaceable></arg>
    <arg><option>--dry-run</option></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
@@ -45,8 +47,9 @@ which deletes all old generations of all profiles in
 impossible); and
 <option>--delete-older-than</option> <replaceable>period</replaceable>,
 where period is a value such as <literal>30d</literal>, which deletes
-all non-current generations that are older than the specified number of
-days in all profiles in <filename>/nix/var/nix/profiles</filename>.
+all generations older than the specified number of days in all profiles
+in <filename>/nix/var/nix/profiles</filename> (except for the generations
+that were active at that point in time).
 </para>

 </refsection>
@@ -7,7 +7,7 @@
  <refentrytitle>nix-copy-closure</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -22,14 +22,14 @@
      <arg choice='plain'><option>--to</option></arg>
      <arg choice='plain'><option>--from</option></arg>
    </group>
-    <arg><option>--sign</option></arg>
    <arg><option>--gzip</option></arg>
-    <arg><option>--bzip2</option></arg>
-    <arg><option>--xz</option></arg>
-    <arg><option>--show-progress</option></arg>
+    <!--
+    <arg><option>- -show-progress</option></arg>
+    -->
    <arg><option>--include-outputs</option></arg>
    <arg><option>--use-substitutes</option></arg>
    <arg><option>-s</option></arg>
+    <arg><option>-v</option></arg>
    <arg choice='plain'>
      <replaceable>user@</replaceable><replaceable>machine</replaceable>
    </arg>
@@ -42,7 +42,7 @@

 <para><command>nix-copy-closure</command> gives you an easy and
 efficient way to exchange software between machines.  Given one or
-more Nix store paths <replaceable>paths</replaceable> on the local
+more Nix store <replaceable>paths</replaceable> on the local
 machine, <command>nix-copy-closure</command> computes the closure of
 those paths (i.e. all their dependencies in the Nix store), and copies
 all paths in the closure to the remote machine via the
@@ -86,39 +86,21 @@ those paths.  If this bothers you, use

  </varlistentry>

-  <varlistentry><term><option>--sign</option></term>
+  <varlistentry><term><option>--gzip</option></term>

-    <listitem><para>Let the sending machine cryptographically sign the
-    dump of each path with the key in
-    <filename><replaceable>sysconfdir</replaceable>/nix/signing-key.sec</filename>.
-    If the user on the target machine does not have direct access to
-    the Nix store (i.e., if the target machine has a multi-user Nix
-    installation), then the target machine will check the dump against
-    <filename><replaceable>sysconfdir</replaceable>/nix/signing-key.pub</filename>
-    before unpacking it in its Nix store.  This allows secure sharing
-    of store paths between untrusted users on two machines, provided
-    that there is a trust relation between the Nix installations on
-    both machines (namely, they have matching public/secret
-    keys).</para></listitem>
+    <listitem><para>Enable compression of the SSH
+    connection.</para></listitem>

  </varlistentry>

-  <varlistentry><term><option>--gzip</option> / <option>--bzip2</option> / <option>--xz</option></term>
-
-    <listitem><para>Compress the dump of each path with respectively
-    <command>gzip</command>, <command>bzip2</command> or
-    <command>xz</command> before sending it.  The corresponding
-    decompression program must be installed on the target
-    machine.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--show-progress</option></term>
+  <!--
+  <varlistentry><term><option>- -show-progress</option></term>

    <listitem><para>Show the progress of each path's transfer as it's made.
    This requires the <command>pv</command> utility to be in <envar>PATH</envar>.</para></listitem>

  </varlistentry>
+  -->

  <varlistentry><term><option>--include-outputs</option></term>

@@ -139,6 +121,12 @@ those paths.  If this bothers you, use

  </varlistentry>

+  <varlistentry><term><option>-v</option></term>
+
+    <listitem><para>Show verbose output.</para></listitem>
+
+  </varlistentry>
+
 </variablelist>

 </refsection>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-daemon">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-daemon">

 <refmeta>
  <refentrytitle>nix-daemon</refentrytitle>
  <manvolnum>8</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-env">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-env">

 <refmeta>
  <refentrytitle>nix-env</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -65,6 +66,75 @@ be performed.  These are documented below.</para>



+<!--######################################################################-->
+
+<refsection><title>Selectors</title>
+
+<para>Several commands, such as <command>nix-env -q</command> and
+<command>nix-env -i</command>, take a list of arguments that specify
+the packages on which to operate. These are extended regular
+expressions that must match the entire name of the package. (For
+details on regular expressions, see
+<citerefentry><refentrytitle>regex</refentrytitle><manvolnum>7</manvolnum></citerefentry>.)
+The match is case-sensitive. The regular expression can optionally be
+followed by a dash and a version number; if omitted, any version of
+the package will match.  Here are some examples:
+
+<variablelist>
+
+  <varlistentry>
+    <term><literal>firefox</literal></term>
+    <listitem><para>Matches the package name
+    <literal>firefox</literal> and any version.</para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><literal>firefox-32.0</literal></term>
+    <listitem><para>Matches the package name
+    <literal>firefox</literal> and version
+    <literal>32.0</literal>.</para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><literal>gtk\\+</literal></term>
+    <listitem><para>Matches the package name
+    <literal>gtk+</literal>. The <literal>+</literal> character must
+    be escaped using a backslash to prevent it from being interpreted
+    as a quantifier, and the backslash must be escaped in turn with
+    another backslash to ensure that the shell passes it
+    on.</para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><literal>.\*</literal></term>
+    <listitem><para>Matches any package name. This is the default for
+    most commands.</para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><literal>'.*zip.*'</literal></term>
+    <listitem><para>Matches any package name containing the string
+    <literal>zip</literal>. Note the dots: <literal>'*zip*'</literal>
+    does not work, because in a regular expression, the character
+    <literal>*</literal> is interpreted as a
+    quantifier.</para></listitem>
+  </varlistentry>
+
+  <varlistentry>
+    <term><literal>'.*(firefox|chromium).*'</literal></term>
+    <listitem><para>Matches any package name containing the strings
+    <literal>firefox</literal> or
+    <literal>chromium</literal>.</para></listitem>
+  </varlistentry>
+
+</variablelist>
+
+</para>
+
+</refsection>
+
+
+
 <!--######################################################################-->

 <refsection><title>Common options</title>
@@ -84,7 +154,15 @@ also <xref linkend="sec-common-options" />.</phrase></para>
    <option>--install</option>, <option>--upgrade</option>, and
    <option>--query --available</option> operations to obtain
    derivations.  The default is
-    <filename>~/.nix-defexpr</filename>.</para></listitem>
+    <filename>~/.nix-defexpr</filename>.</para>
+
+    <para>If the argument starts with <literal>http://</literal> or
+    <literal>https://</literal>, it is interpreted as the URL of a
+    tarball that will be downloaded and unpacked to a temporary
+    location. The tarball must include a single top-level directory
+    containing at least a file named <filename>default.nix</filename>.</para>
+
+    </listitem>

  </varlistentry>

@@ -261,7 +339,7 @@ number of possible ways:
  <emphasis>attribute paths</emphasis> that select attributes from the
  top-level Nix expression.  This is faster than using derivation
  names and unambiguous.  To find out the attribute paths of available
-  packages, use <literal>nix-env -qaP '*'</literal>.</para></listitem>
+  packages, use <literal>nix-env -qaP</literal>.</para></listitem>

  <listitem><para>If <option>--from-profile</option>
  <replaceable>path</replaceable> is given,
@@ -289,6 +367,10 @@ number of possible ways:
  linkend="rsec-nix-store-realise">realised</link> and
  installed.</para></listitem>

+  <listitem><para>By default all outputs are installed for each derivation.
+  That can be reduced by setting <literal>meta.outputsToInstall</literal>.
+  </para></listitem> <!-- TODO: link nixpkgs docs on the ability to override those. -->
+
 </itemizedlist>

 </para>
@@ -300,7 +382,7 @@ number of possible ways:

 <variablelist>

-  <varlistentry><term><option>--prebuild-only</option> / <option>-b</option></term>
+  <varlistentry><term><option>--prebuilt-only</option> / <option>-b</option></term>

    <listitem><para>Use only derivations for which a substitute is
    registered, i.e., there is a pre-built binary available that can
@@ -325,7 +407,7 @@ number of possible ways:
    <term><option>-r</option></term>

    <listitem><para>Remove all previously installed packages first.
-    This is equivalent to running <literal>nix-env -e '*'</literal>
+    This is equivalent to running <literal>nix-env -e '.*'</literal>
    first, except that everything happens in a single
    transaction.</para></listitem>

@@ -346,7 +428,7 @@ $ nix-env --install gcc-3.3.2
 installing `gcc-3.3.2'
 uninstalling `gcc-3.1'</screen>

-Note the the previously installed version is removed, since
+Note the previously installed version is removed, since
 <option>--preserve-installed</option> was not specified.</para>

 <para>To install an arbitrary version:
@@ -368,7 +450,7 @@ $ nix-env -i -A xorg.xorgserver</screen>
 <para>To install all derivations in the Nix expression <filename>foo.nix</filename>:

 <screen>
-$ nix-env -f ~/foo.nix -i '*'</screen>
+$ nix-env -f ~/foo.nix -i '.*'</screen>

 </para>

@@ -411,21 +493,27 @@ set returned by calling the function defined in
 source:

 <screen>
-$ nix-env -f pkgs/top-level/all-packages.nix -i f-spot --dry-run
+$ nix-env -f '&lt;nixpkgs>' -iA hello --dry-run
 (dry run; not doing anything)
-installing `f-spot-0.0.10'
-the following derivations will be built:
-  /nix/store/0g63jv9aagwbgci4nnzs2dkxqz84kdja-libgnomeprintui-2.12.1.tar.bz2.drv
-  /nix/store/0gfarvxq6sannsdw8a1ir40j1ys2mqb4-ORBit2-2.14.2.tar.bz2.drv
-  /nix/store/0i9gs5zc04668qiy60ga2rc16abkj7g8-sqlite-2.8.17.drv
-  <replaceable>...</replaceable>
-the following paths will be substituted:
-  /nix/store/8zbipvm4gp9jfqh9nnk1n3bary1a37gs-perl-XML-Parser-2.34
-  /nix/store/b8a2bg7gnyvvvjjibp4axg9x1hzkw36c-mono-1.1.4
+installing ‘hello-2.10’
+these paths will be fetched (0.04 MiB download, 0.19 MiB unpacked):
+  /nix/store/wkhdf9jinag5750mqlax6z2zbwhqb76n-hello-2.10
  <replaceable>...</replaceable></screen>

 </para>

+<para>To install Firefox from the latest revision in the Nixpkgs/NixOS
+14.12 channel:
+
+<screen>
+$ nix-env -f https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz -iA firefox
+</screen>
+
+(The GitHub repository <literal>nixpkgs-channels</literal> is updated
+automatically from the main <literal>nixpkgs</literal> repository
+after certain tests have succeeded and binaries have been built and
+uploaded to the binary cache at <uri>cache.nixos.org</uri>.)</para>
+
 </refsection>

 </refsection>
@@ -536,7 +624,7 @@ upgrading `gcc-3.4' to `gcc-3.3.2'
 $ nix-env --upgrade pan
 <lineannotation>(no upgrades available, so nothing happens)</lineannotation>

-$ nix-env -u '*' <lineannotation>(try to upgrade everything)</lineannotation>
+$ nix-env -u <lineannotation>(try to upgrade everything)</lineannotation>
 upgrading `hello-2.1.2' to `hello-2.1.3'
 upgrading `mozilla-1.2' to `mozilla-1.4'</screen>

@@ -623,7 +711,45 @@ paths designated by the symbolic names

 <screen>
 $ nix-env --uninstall gcc
-$ nix-env -e '*' <lineannotation>(remove everything)</lineannotation></screen>
+$ nix-env -e '.*' <lineannotation>(remove everything)</lineannotation></screen>
+
+</refsection>
+
+</refsection>
+
+
+
+<!--######################################################################-->
+
+<refsection xml:id="rsec-nix-env-set"><title>Operation <option>--set</option></title>
+
+<refsection><title>Synopsis</title>
+
+<cmdsynopsis>
+  <command>nix-env</command>
+  <arg choice='plain'><option>--set</option></arg>
+  <arg choice='plain'><replaceable>drvname</replaceable></arg>
+</cmdsynopsis>
+</refsection>
+
+<refsection><title>Description</title>
+
+<para>The <option>--set</option> operation modifies the current generation of a
+profile so that it contains exactly the specified derivation, and nothing else.
+</para>
+
+</refsection>
+
+<refsection><title>Examples</title>
+
+<para>
+The following updates a profile such that its current generation will contain
+just Firefox:
+
+<screen>
+$ nix-env -p /nix/var/nix/profiles/browser --set firefox</screen>
+
+</para>

 </refsection>

@@ -699,7 +825,7 @@ After this, <command>nix-env -u</command> will ignore Firefox.</para>
 Firefox while the old remains part of the profile:

 <screen>
-$ nix-env -q \*
+$ nix-env -q
 firefox-2.0.0.9 <lineannotation>(the current one)</lineannotation>

 $ nix-env --preserve-installed -i firefox-2.0.0.11
@@ -715,7 +841,7 @@ setting flag on `firefox-2.0.0.9'
 $ nix-env --preserve-installed -i firefox-2.0.0.11
 installing `firefox-2.0.0.11'

-$ nix-env -q \*
+$ nix-env -q
 firefox-2.0.0.11 <lineannotation>(the enabled one)</lineannotation>
 firefox-2.0.0.9 <lineannotation>(the disabled one)</lineannotation></screen>

@@ -816,8 +942,7 @@ profile (<option>--installed</option>), or the derivations that are
 available for installation in the active Nix expression
 (<option>--available</option>).  It only prints information about
 derivations whose symbolic name matches one of
-<replaceable>names</replaceable>.  The wildcard <literal>*</literal>
-shows all derivations.</para>
+<replaceable>names</replaceable>.</para>

 <para>The derivations are sorted by their <literal>name</literal>
 attributes.</para>
@@ -885,7 +1010,7 @@ user environment elements, etc. -->

  </varlistentry>

-  <varlistentry><term><option>--prebuild-only</option> / <option>-b</option></term>
+  <varlistentry><term><option>--prebuilt-only</option> / <option>-b</option></term>

    <listitem><para>Show only derivations for which a substitute is
    registered, i.e., there is a pre-built binary available that can
@@ -1022,48 +1147,102 @@ user environment elements, etc. -->

 <refsection><title>Examples</title>

+<para>To show installed packages:
+
 <screen>
-$ nix-env -q '*' <lineannotation>(show installed derivations)</lineannotation>
+$ nix-env -q
 bison-1.875c
 docbook-xml-4.2
 firefox-1.0.4
 MPlayer-1.0pre7
 ORBit2-2.8.3
-...
+<replaceable>…</replaceable>
+</screen>

-$ nix-env -qa '*' <lineannotation>(show available derivations)</lineannotation>
+</para>
+
+<para>To show available packages:
+
+<screen>
+$ nix-env -qa
 firefox-1.0.7
 GConf-2.4.0.1
 MPlayer-1.0pre7
 ORBit2-2.8.3
-...
+<replaceable>…</replaceable>
+</screen>

-$ nix-env -qas '*' <lineannotation>(show status of available derivations)</lineannotation>
+</para>
+
+<para>To show the status of available packages:
+
+<screen>
+$ nix-env -qas
 -P- firefox-1.0.7   <lineannotation>(not installed but present)</lineannotation>
 --S GConf-2.4.0.1   <lineannotation>(not present, but there is a substitute for fast installation)</lineannotation>
 --S MPlayer-1.0pre3 <lineannotation>(i.e., this is not the installed MPlayer, even though the version is the same!)</lineannotation>
 IP- ORBit2-2.8.3    <lineannotation>(installed and by definition present)</lineannotation>
-...
+<replaceable>…</replaceable>
+</screen>

-<lineannotation>(show available derivations in the Nix expression <!-- !!! <filename>-->foo.nix<!-- </filename> -->)</lineannotation>
-$ nix-env -f ./foo.nix -qa '*'
+</para>
+
+<para>To show available packages in the Nix expression <filename>foo.nix</filename>:
+
+<screen>
+$ nix-env -f ./foo.nix -qa
 foo-1.2.3
+</screen>

-$ nix-env -qc '*' <lineannotation>(compare installed versions to what’s available)</lineannotation>
+</para>
+
+<para>To compare installed versions to what’s available:
+
+<screen>
+$ nix-env -qc
 <replaceable>...</replaceable>
 acrobat-reader-7.0 - ?      <lineannotation>(package is not available at all)</lineannotation>
 autoconf-2.59      = 2.59   <lineannotation>(same version)</lineannotation>
 firefox-1.0.4      &lt; 1.0.7  <lineannotation>(a more recent version is available)</lineannotation>
 <replaceable>...</replaceable>
+</screen>

-<lineannotation>(show info about a specific package, in XML)</lineannotation>
-$ nix-env -qa --xml --description firefox
-<![CDATA[<?xml version='1.0' encoding='utf-8'?>
-<items>
-  <item attrPath="0.0.firefoxWrapper"
-    description="Mozilla Firefox - the browser, reloaded (with various plugins)"
-    name="firefox-1.5.0.7" system="i686-linux" />
-</items>]]></screen>
+</para>
+
+<para>To show all packages with “<literal>zip</literal>” in the name:
+
+<screen>
+$ nix-env -qa '.*zip.*'
+bzip2-1.0.6
+gzip-1.6
+zip-3.0
+<replaceable>…</replaceable>
+</screen>
+
+</para>
+
+<para>To show all packages with “<literal>firefox</literal>” or
+“<literal>chromium</literal>” in the name:
+
+<screen>
+$ nix-env -qa '.*(firefox|chromium).*'
+chromium-37.0.2062.94
+chromium-beta-38.0.2125.24
+firefox-32.0.3
+firefox-with-plugins-13.0.1
+<replaceable>…</replaceable>
+</screen>
+
+</para>
+
+<para>To show all packages in the latest revision of the Nixpkgs
+repository:
+
+<screen>
+$ nix-env -f https://github.com/NixOS/nixpkgs/archive/master.tar.gz -qa
+</screen>
+
+</para>

 </refsection>

@@ -1170,7 +1349,8 @@ $ nix-env --list-generations
 profile.  The generations can be a list of generation numbers, the
 special value <literal>old</literal> to delete all non-current
 generations, or a value such as <literal>30d</literal> to delete all
-non-current generations older than the specified number of days.
+generations older than the specified number of days (except for the
+generation that was active at that point in time).
 Periodically deleting old generations is important to make garbage
 collection effective.</para>

@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-hash">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-hash">
  
 <refmeta>
  <refentrytitle>nix-hash</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-instantiate">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-instantiate">

 <refmeta>
  <refentrytitle>nix-instantiate</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -44,7 +45,7 @@
    <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
    <sbr/>
    <command>nix-instantiate</command>
-    <arg choice='plain'><option>--file-file</option></arg>
+    <arg choice='plain'><option>--find-file</option></arg>
    <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
@@ -103,9 +104,10 @@ input.</para>
  <varlistentry><term><option>--find-file</option></term>

    <listitem><para>Look up the given files in Nix’s search path (as
-    specified by the <envar>NIX_PATH</envar> environment variable).
-    If found, print the corresponding absolute paths on standard
-    output.  For instance, if <envar>NIX_PATH</envar> is
+    specified by the <envar linkend="env-NIX_PATH">NIX_PATH</envar>
+    environment variable).  If found, print the corresponding absolute
+    paths on standard output.  For instance, if
+    <envar>NIX_PATH</envar> is
    <literal>nixpkgs=/home/alice/nixpkgs</literal>, then
    <literal>nix-instantiate --find-file nixpkgs/default.nix</literal>
    will print
@@ -124,6 +126,15 @@ input.</para>

  </varlistentry>

+  <varlistentry><term><option>--json</option></term>
+
+    <listitem><para>When used with <option>--parse</option> and
+    <option>--eval</option>, print the resulting expression as an
+    JSON representation of the abstract syntax tree rather than as an
+    ATerm.</para></listitem>
+
+  </varlistentry>
+
  <varlistentry><term><option>--strict</option></term>

    <listitem><para>When used with <option>--eval</option>,
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-prefetch-url">
-  
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-prefetch-url">
+
 <refmeta>
  <refentrytitle>nix-prefetch-url</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -19,6 +20,7 @@
  <cmdsynopsis>
    <command>nix-prefetch-url</command>
    <arg><option>--type</option> <replaceable>hashAlgo</replaceable></arg>
+    <arg><option>--print-path</option></arg>
    <arg choice='plain'><replaceable>url</replaceable></arg>
    <arg><replaceable>hash</replaceable></arg>
  </cmdsynopsis>
@@ -53,8 +55,8 @@ error if signaled if the actual hash of the file does not match the
 specified hash.</para>

 <para>This command prints the hash on standard output.  Additionally,
-if the environment variable <envar>PRINT_PATH</envar> is set, the path
-of the downloaded file in the Nix store is also printed.</para>
+if the option <option>--print-path</option> is used, the path of the
+downloaded file in the Nix store is also printed.</para>

 </refsection>

@@ -62,7 +64,7 @@ of the downloaded file in the Nix store is also printed.</para>
 <refsection><title>Options</title>

 <variablelist>
-  
+
  <varlistentry><term><option>--type</option> <replaceable>hashAlgo</replaceable></term>

    <listitem><para>Use the specified cryptographic hash algorithm,
@@ -72,6 +74,35 @@ of the downloaded file in the Nix store is also printed.</para>

  </varlistentry>

+  <varlistentry><term><option>--print-path</option></term>
+
+    <listitem><para>Print the store path of the downloaded file on
+    standard output.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--unpack</option></term>
+
+    <listitem><para>Unpack the archive (which must be a tarball or zip
+    file) and add the result to the Nix store. The resulting hash can
+    be used with functions such as Nixpkgs’s
+    <varname>fetchzip</varname> or
+    <varname>fetchFromGitHub</varname>.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--name</option></term>
+
+    <listitem><para>Override the name of the file in the Nix store. By
+    default, this is
+    <literal><replaceable>hash</replaceable>-<replaceable>basename</replaceable></literal>,
+    where <replaceable>basename</replaceable> is the last component of
+    <replaceable>url</replaceable>. Overriding the name is necessary
+    when <replaceable>basename</replaceable> contains characters that
+    are not allowed in Nix store paths.</para></listitem>
+
+  </varlistentry>
+
 </variablelist>

 </refsection>
@@ -80,14 +111,19 @@ of the downloaded file in the Nix store is also printed.</para>
 <refsection><title>Examples</title>

 <screen>
-$ nix-prefetch-url ftp://ftp.nluug.nl/pub/gnu/make/make-3.80.tar.bz2
-0bbd1df101bc0294d440471e50feca71
+$ nix-prefetch-url ftp://ftp.gnu.org/pub/gnu/hello/hello-2.10.tar.gz
+0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i

-$ PRINT_PATH=1 nix-prefetch-url ftp://ftp.nluug.nl/pub/gnu/make/make-3.80.tar.bz2
-0bbd1df101bc0294d440471e50feca71
-/nix/store/wvyz8ifdn7wyz1p3pqyn0ra45ka2l492-make-3.80.tar.bz2</screen>
+$ nix-prefetch-url --print-path mirror://gnu/hello/hello-2.10.tar.gz
+0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i
+/nix/store/3x7dwzq014bblazs7kq20p9hyzz0qh8g-hello-2.10.tar.gz
+
+$ nix-prefetch-url --unpack --print-path https://github.com/NixOS/patchelf/archive/0.8.tar.gz
+079agjlv0hrv7fxnx9ngipx14gyncbkllxrp9cccnh3a50fxcmy7
+/nix/store/19zrmhm3m40xxaw81c8cqm6aljgrnwj2-0.8.tar.gz
+</screen>

 </refsection>

-    
+
 </refentry>
@@ -0,0 +1,374 @@
+<refentry xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-shell">
+
+<refmeta>
+  <refentrytitle>nix-shell</refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo class="source">Nix</refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
+</refmeta>
+
+<refnamediv>
+  <refname>nix-shell</refname>
+  <refpurpose>start an interactive shell based on a Nix expression</refpurpose>
+</refnamediv>
+
+<refsynopsisdiv>
+  <cmdsynopsis>
+    <command>nix-shell</command>
+    <arg><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
+    <arg><option>--argstr</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
+    <arg>
+      <group choice='req'>
+        <arg choice='plain'><option>--attr</option></arg>
+        <arg choice='plain'><option>-A</option></arg>
+      </group>
+      <replaceable>attrPath</replaceable>
+    </arg>
+    <arg><option>--command</option> <replaceable>cmd</replaceable></arg>
+    <arg><option>--run</option> <replaceable>cmd</replaceable></arg>
+    <arg><option>--exclude</option> <replaceable>regexp</replaceable></arg>
+    <arg><option>--pure</option></arg>
+    <group choice='req'>
+      <group choice='plain'>
+        <group>
+          <arg choice='plain'><option>--packages</option></arg>
+          <arg choice='plain'><option>-p</option></arg>
+        </group>
+        <replaceable>packages</replaceable>
+      </group>
+      <arg><replaceable>path</replaceable></arg>
+    </group>
+  </cmdsynopsis>
+</refsynopsisdiv>
+
+<refsection><title>Description</title>
+
+<para>The command <command>nix-shell</command> will build the
+dependencies of the specified derivation, but not the derivation
+itself.  It will then start an interactive shell in which all
+environment variables defined by the derivation
+<replaceable>path</replaceable> have been set to their corresponding
+values, and the script <literal>$stdenv/setup</literal> has been
+sourced.  This is useful for reproducing the environment of a
+derivation for development.</para>
+
+<para>If <replaceable>path</replaceable> is not given,
+<command>nix-shell</command> defaults to
+<filename>shell.nix</filename> if it exists, and
+<filename>default.nix</filename> otherwise.</para>
+
+<para>If <replaceable>path</replaceable> starts with
+<literal>http://</literal> or <literal>https://</literal>, it is
+interpreted as the URL of a tarball that will be downloaded and
+unpacked to a temporary location. The tarball must include a single
+top-level directory containing at least a file named
+<filename>default.nix</filename>.</para>
+
+<para>If the derivation defines the variable
+<varname>shellHook</varname>, it will be evaluated after
+<literal>$stdenv/setup</literal> has been sourced.  Since this hook is
+not executed by regular Nix builds, it allows you to perform
+initialisation specific to <command>nix-shell</command>.  For example,
+the derivation attribute
+
+<programlisting>
+shellHook =
+  ''
+    echo "Hello shell"
+  '';
+</programlisting>
+
+will cause <command>nix-shell</command> to print <literal>Hello shell</literal>.</para>
+
+</refsection>
+
+
+<refsection><title>Options</title>
+
+<para>All options not listed here are passed to <command>nix-store
+--realise</command>, except for <option>--arg</option> and
+<option>--attr</option> / <option>-A</option> which are passed to
+<command>nix-instantiate</command>.  <phrase condition="manual">See
+also <xref linkend="sec-common-options" />.</phrase></para>
+
+<variablelist>
+
+  <varlistentry><term><option>--command</option> <replaceable>cmd</replaceable></term>
+
+    <listitem><para>In the environment of the derivation, run the
+    shell command <replaceable>cmd</replaceable>. This command is
+    executed in an interactive shell. (Use <option>--run</option> to
+    use a non-interactive shell instead.) However, a call to
+    <literal>exit</literal> is implicitly added to the command, so the
+    shell will exit after running the command. To prevent this, add
+    <literal>return</literal> at the end; e.g. <literal>--command
+    "echo Hello; return"</literal> will print <literal>Hello</literal>
+    and then drop you into the interactive shell. This can be useful
+    for doing any additional initialisation.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--run</option> <replaceable>cmd</replaceable></term>
+
+    <listitem><para>Like <option>--command</option>, but executes the
+    command in a non-interactive shell. This means (among other
+    things) that if you hit Ctrl-C while the command is running, the
+    shell exits.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--exclude</option> <replaceable>regexp</replaceable></term>
+
+    <listitem><para>Do not build any dependencies whose store path
+    matches the regular expression <replaceable>regexp</replaceable>.
+    This option may be specified multiple times.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--pure</option></term>
+
+    <listitem><para>If this flag is specified, the environment is
+    almost entirely cleared before the interactive shell is started,
+    so you get an environment that more closely corresponds to the
+    “real” Nix build.  A few variables, in particular
+    <envar>HOME</envar>, <envar>USER</envar> and
+    <envar>DISPLAY</envar>, are retained.  Note that
+    <filename>~/.bashrc</filename> and (depending on your Bash
+    installation) <filename>/etc/bashrc</filename> are still sourced,
+    so any variables set there will affect the interactive
+    shell.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>--packages</option> / <option>-p</option></term>
+
+    <listitem><para>Set up an environment in which the specified
+    packages are present.  The command line arguments are interpreted
+    as attribute names inside the Nix Packages collection.  Thus,
+    <literal>nix-shell -p libjpeg openjdk</literal> will start a shell
+    in which the packages denoted by the attribute names
+    <varname>libjpeg</varname> and <varname>openjdk</varname> are
+    present.</para></listitem>
+
+  </varlistentry>
+
+  <varlistentry><term><option>-i</option> <replaceable>interpreter</replaceable></term>
+
+    <listitem><para>The chained script interpreter to be invoked by
+    <command>nix-shell</command>. Only applicable in
+    <literal>#!</literal>-scripts (described <link
+    linkend="ssec-nix-shell-shebang">below</link>).</para>
+
+    </listitem></varlistentry>
+
+</variablelist>
+
+<para>The following common options are supported:</para>
+
+<variablelist condition="manpage">
+  <xi:include href="opt-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='opt-common']/*)" />
+</variablelist>
+
+</refsection>
+
+
+<refsection><title>Environment variables</title>
+
+<variablelist>
+
+  <varlistentry><term><envar>NIX_BUILD_SHELL</envar></term>
+    
+    <listitem><para>Shell used to start the interactive environment. 
+    Defaults to the <command>bash</command> found in <envar>PATH</envar>.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</refsection>
+
+
+<refsection><title>Examples</title>
+
+<para>To build the dependencies of the package Pan, and start an
+interactive shell in which to build it:
+
+<screen>
+$ nix-shell '&lt;nixpkgs>' -A pan
+[nix-shell]$ unpackPhase
+[nix-shell]$ cd pan-*
+[nix-shell]$ configurePhase
+[nix-shell]$ buildPhase
+[nix-shell]$ ./pan/gui/pan
+</screen>
+
+To clear the environment first, and do some additional automatic
+initialisation of the interactive shell:
+
+<screen>
+$ nix-shell '&lt;nixpkgs>' -A pan --pure \
+    --command 'export NIX_DEBUG=1; export NIX_CORES=8; return'
+</screen>
+
+Nix expressions can also be given on the command line.  For instance,
+the following starts a shell containing the packages
+<literal>sqlite</literal> and <literal>libX11</literal>:
+
+<screen>
+$ nix-shell -E 'with import &lt;nixpkgs> { }; runCommand "dummy" { buildInputs = [ sqlite xorg.libX11 ]; } ""'
+</screen>
+
+A shorter way to do the same is:
+
+<screen>
+$ nix-shell -p sqlite xorg.libX11
+[nix-shell]$ echo $NIX_LDFLAGS
+… -L/nix/store/j1zg5v…-sqlite-3.8.0.2/lib -L/nix/store/0gmcz9…-libX11-1.6.1/lib …
+</screen>
+
+The <command>-p</command> flag looks up Nixpkgs in the Nix search
+path. You can override it by passing <option>-I</option> or setting
+<envar>NIX_PATH</envar>. For example, the following gives you a shell
+containing the Pan package from a specific revision of Nixpkgs:
+
+<screen>
+$ nix-shell -p pan -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/8a3eea054838b55aca962c3fbde9c83c102b8bf2.tar.gz
+
+[nix-shell:~]$ pan --version
+Pan 0.139
+</screen>
+
+</para>
+
+</refsection>
+
+
+<refsection xml:id="ssec-nix-shell-shebang"><title>Use as a <literal>#!</literal>-interpreter</title>
+
+<para>You can use <command>nix-shell</command> as a script interpreter
+to allow scripts written in arbitrary languages to obtain their own
+dependencies via Nix. This is done by starting the script with the
+following lines:
+
+<programlisting>
+#! /usr/bin/env nix-shell
+#! nix-shell -i <replaceable>real-interpreter</replaceable> -p <replaceable>packages</replaceable>
+</programlisting>
+
+where <replaceable>real-interpreter</replaceable> is the “real” script
+interpreter that will be invoked by <command>nix-shell</command> after
+it has obtained the dependencies and initialised the environment, and
+<replaceable>packages</replaceable> are the attribute names of the
+dependencies in Nixpkgs.</para>
+
+<para>The lines starting with <literal>#! nix-shell</literal> specify
+<command>nix-shell</command> options (see above). Note that you cannot
+write <literal>#! /usr/bin/env nix-shell -i ...</literal> because
+many operating systems only allow one argument in
+<literal>#!</literal> lines.</para>
+
+<para>For example, here is a Python script that depends on Python and
+the <literal>prettytable</literal> package:
+
+<programlisting>
+#! /usr/bin/env nix-shell
+#! nix-shell -i python -p python pythonPackages.prettytable
+
+import prettytable
+
+# Print a simple table.
+t = prettytable.PrettyTable(["N", "N^2"])
+for n in range(1, 10): t.add_row([n, n * n])
+print t
+</programlisting>
+
+</para>
+
+<para>Similarly, the following is a Perl script that specifies that it
+requires Perl and the <literal>HTML::TokeParser::Simple</literal> and
+<literal>LWP</literal> packages:
+
+<programlisting>
+#! /usr/bin/env nix-shell
+#! nix-shell -i perl -p perl perlPackages.HTMLTokeParserSimple perlPackages.LWP
+
+use HTML::TokeParser::Simple;
+
+# Fetch nixos.org and print all hrefs.
+my $p = HTML::TokeParser::Simple->new(url => 'http://nixos.org/');
+
+while (my $token = $p->get_tag("a")) {
+    my $href = $token->get_attr("href");
+    print "$href\n" if $href;
+}
+</programlisting>
+
+</para>
+
+<para>Finally, the following Haskell script uses a specific branch of
+Nixpkgs/NixOS (the 14.12 stable branch):
+
+<programlisting><![CDATA[
+#! /usr/bin/env nix-shell
+#! nix-shell -i runghc -p haskellPackages.ghc haskellPackages.HTTP haskellPackages.tagsoup
+#! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz
+
+import Network.HTTP
+import Text.HTML.TagSoup
+
+-- Fetch nixos.org and print all hrefs.
+main = do
+  resp <- Network.HTTP.simpleHTTP (getRequest "http://nixos.org/")
+  body <- getResponseBody resp
+  let tags = filter (isTagOpenName "a") $ parseTags body
+  let tags' = map (fromAttrib "href") tags
+  mapM_ putStrLn $ filter (/= "") tags'
+]]></programlisting>
+
+If you want to be even more precise, you can specify a specific
+revision of Nixpkgs:
+
+<programlisting>
+#! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/0672315759b3e15e2121365f067c1c8c56bb4722.tar.gz
+</programlisting>
+
+</para>
+
+<para>The examples above all used <option>-p</option> to get
+dependencies from Nixpkgs. You can also use a Nix expression to build
+your own dependencies. For example, the Python example could have been
+written as:
+
+<programlisting>
+#! /usr/bin/env nix-shell
+#! nix-shell deps.nix -i python
+</programlisting>
+
+where the file <filename>deps.nix</filename> in the same directory
+as the <literal>#!</literal>-script contains:
+
+<programlisting>
+with import &lt;nixpkgs> {};
+
+runCommand "dummy" { buildInputs = [ python pythonPackages.prettytable ]; } ""
+</programlisting>
+
+</para>
+
+</refsection>
+
+
+<refsection condition="manpage"><title>Environment variables</title>
+
+<variablelist>
+  <xi:include href="env-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='env-common']/*)" />
+</variablelist>
+
+</refsection>
+
+
+</refentry>
@@ -1,13 +1,14 @@
 <refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-store">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-nix-store">

 <refmeta>
  <refentrytitle>nix-store</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
+  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>

 <refnamediv>
@@ -111,7 +112,7 @@ lrwxrwxrwx    1 ... 2005-03-13 21:10 /home/eelco/bla/result -> /nix/store/1r1134
    </listitem>

  </varlistentry>
-    
+
 </variablelist>

 <variablelist condition="manpage">
@@ -120,7 +121,7 @@ lrwxrwxrwx    1 ... 2005-03-13 21:10 /home/eelco/bla/result -> /nix/store/1r1134

 </refsection>

-  
+

 <!--######################################################################-->

@@ -141,7 +142,7 @@ lrwxrwxrwx    1 ... 2005-03-13 21:10 /home/eelco/bla/result -> /nix/store/1r1134
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--realise</option> essentially “builds”
 the specified store paths.  Realisation is a somewhat overloaded term:

@@ -193,17 +194,36 @@ printed.)</para>

  </varlistentry>

+  <varlistentry><term><option>--check</option></term>
+
+    <listitem><para>This option allows you to check whether a
+    derivation is deterministic. It rebuilds the specified derivation
+    and checks whether the result is bitwise-identical with the
+    existing outputs, printing an error if that’s not the case. The
+    outputs of the specified derivation must already exist. When used
+    with <option>-K</option>, if an output path is not identical to
+    the corresponding output from the previous build, the new output
+    path is left in
+    <filename>/nix/store/<replaceable>name</replaceable>-check.</filename></para>
+
+    <para>See also the <option>build-repeat</option> configuration
+    option, which repeats a derivation a number of times and prevents
+    its outputs from being registered as “valid” in the Nix store
+    unless they are identical.</para></listitem>
+
+  </varlistentry>
+
 </variablelist>

 </refsection>
-            
+

 <refsection><title>Examples</title>

 <para>This operation is typically used to build store derivations
 produced by <link
 linkend="sec-nix-instantiate"><command>nix-instantiate</command></link>:
-    
+
 <screen>
 $ nix-store -r $(nix-instantiate ./test.nix)
 /nix/store/31axcgrlbfsxzmfff1gyj1bf62hvkby2-aterm-2.3.1</screen>
@@ -211,12 +231,79 @@ $ nix-store -r $(nix-instantiate ./test.nix)
 This is essentially what <link
 linkend="sec-nix-build"><command>nix-build</command></link> does.</para>

+<para>To test whether a previously-built derivation is deterministic:
+
+<screen>
+$ nix-build -r '&lt;nixpkgs>' -A hello --check -K
+</screen>
+
+</para>
+
 </refsection>


 </refsection>

-  
+
+
+<!--######################################################################-->
+
+<refsection xml:id='rsec-nix-store-serve'><title>Operation <option>--serve</option></title>
+
+<refsection><title>Synopsis</title>
+
+<cmdsynopsis>
+  <command>nix-store</command>
+  <arg choice='plain'><option>--serve</option></arg>
+  <arg><option>--write</option></arg>
+</cmdsynopsis>
+
+</refsection>
+
+<refsection><title>Description</title>
+
+<para>The operation <option>--serve</option> provides access to
+the Nix store over stdin and stdout, and is intended to be used
+as a means of providing Nix store access to a restricted ssh user.
+</para>
+
+<para>The following flags are available:</para>
+
+<variablelist>
+
+  <varlistentry><term><option>--write</option></term>
+
+    <listitem><para>Allow the connected client to request the realization
+    of derivations. In effect, this can be used to make the host act
+    as a build slave.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</refsection>
+
+
+<refsection><title>Examples</title>
+
+<para>To turn a host into a build server, the
+<filename>authorized_keys</filename> file can be used to provide build
+access to a given SSH public key:
+
+<screen>
+$ cat &lt;&lt;EOF >>/root/.ssh/authorized_keys
+command="nice -n20 nix-store --serve --write" ssh-rsa AAAAB3NzaC1yc2EAAAA...
+EOF
+</screen>
+
+</para>
+
+</refsection>
+
+
+</refsection>
+
+

 <!--######################################################################-->

@@ -239,7 +326,7 @@ linkend="sec-nix-build"><command>nix-build</command></link> does.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>Without additional flags, the operation <option>--gc</option>
 performs a garbage collection on the Nix store.  That is, all paths in
 the Nix store not reachable via file system references from a set of
@@ -250,40 +337,40 @@ the Nix store not reachable via file system references from a set of
 <variablelist>

  <varlistentry><term><option>--print-roots</option></term>
-  
+
    <listitem><para>This operation prints on standard output the set
    of roots used by the garbage collector.  What constitutes a root
    is described in <xref linkend="ssec-gc-roots"
    />.</para></listitem>
-    
+
  </varlistentry>

  <varlistentry><term><option>--print-live</option></term>
-  
+
    <listitem><para>This operation prints on standard output the set
    of “live” store paths, which are all the store paths reachable
    from the roots.  Live paths should never be deleted, since that
    would break consistency — it would become possible that
    applications are installed that reference things that are no
    longer present in the store.</para></listitem>
-    
+
  </varlistentry>

  <varlistentry><term><option>--print-dead</option></term>
-  
+
    <listitem><para>This operation prints out on standard output the
    set of “dead” store paths, which is just the opposite of the set
    of live paths: any path in the store that is not live (with
    respect to the roots) is dead.</para></listitem>
-    
+
  </varlistentry>

  <varlistentry><term><option>--delete</option></term>
-  
+
    <listitem><para>This operation performs an actual garbage
    collection.  All dead paths are removed from the
    store.  This is the default.</para></listitem>
-    
+
  </varlistentry>

 </variablelist>
@@ -294,7 +381,7 @@ options control what gets deleted and in what order:
 <variablelist>

  <varlistentry><term><option>--max-freed</option> <replaceable>bytes</replaceable></term>
-  
+
    <listitem><para>Keep deleting paths until at least
    <replaceable>bytes</replaceable> bytes have been deleted, then
    stop.  The argument <replaceable>bytes</replaceable> can be
@@ -302,7 +389,7 @@ options control what gets deleted and in what order:
    <literal>M</literal>, <literal>G</literal> or
    <literal>T</literal>, denoting KiB, MiB, GiB or TiB
    units.</para></listitem>
-    
+
  </varlistentry>

 </variablelist>
@@ -326,7 +413,7 @@ would be freed.</para>
 <refsection><title>Examples</title>

 <para>To delete all unreachable paths, just do:
-    
+
 <screen>
 $ nix-store --gc
 deleting `/nix/store/kq82idx6g0nyzsp2s14gfsc38npai7lf-cairo-1.0.4.tar.gz.drv'
@@ -348,7 +435,7 @@ $ nix-store --gc --max-freed $((100 * 1024 * 1024))</screen>
 </refsection>


-  
+
 <!--######################################################################-->

 <refsection><title>Operation <option>--delete</option></title>
@@ -433,7 +520,7 @@ error: cannot delete path `/nix/store/zq0h41l75vlb4z45kzgjjmsjxvcv1qk7-mesa-6.4'


 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--query</option> displays various bits of
 information about the store paths .  The queries are described below.  At
 most one query can be specified.  The default query is
@@ -453,16 +540,16 @@ query is applied to the target of the symlink.</para>

  <varlistentry><term><option>--use-output</option></term>
    <term><option>-u</option></term>
-  
+
    <listitem><para>For each argument to the query that is a store
    derivation, apply the query to the output path of the derivation
    instead.</para></listitem>
-    
+
  </varlistentry>

  <varlistentry><term><option>--force-realise</option></term>
    <term><option>-f</option></term>
-  
+
    <listitem><para>Realise each argument to the query first (see
    <link linkend="rsec-nix-store-realise"><command>nix-store
    --realise</command></link>).</para></listitem>
@@ -470,12 +557,12 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

 </variablelist>
-        
+
 </refsection>
-    
+

 <refsection xml:id='nixref-queries'><title>Queries</title>
-            
+
 <variablelist>

  <varlistentry><term><option>--outputs</option></term>
@@ -485,7 +572,7 @@ query is applied to the target of the symlink.</para>
    derivations <replaceable>paths</replaceable>.  These are the paths
    that will be produced when the derivation is
    built.</para></listitem>
-    
+
  </varlistentry>

  <varlistentry><term><option>--requisites</option></term>
@@ -500,10 +587,10 @@ query is applied to the target of the symlink.</para>
    <variablelist>

      <varlistentry><term><option>--include-outputs</option></term>
-      
+
        <listitem><para>Also include the output path of store
        derivations, and their closures.</para></listitem>
-        
+
      </varlistentry>

    </variablelist>
@@ -517,13 +604,13 @@ query is applied to the target of the symlink.</para>
    including binaries of build-time-only dependencies) is obtained by
    distributing the closure of a store derivation and specifying the
    option <option>--include-outputs</option>.</para>
-    
+
    </listitem>

  </varlistentry>

  <varlistentry><term><option>--references</option></term>
-  
+
    <listitem><para>Prints the set of <link
    linkend="gloss-reference">references</link> of the store paths
    <replaceable>paths</replaceable>, that is, their immediate
@@ -531,9 +618,9 @@ query is applied to the target of the symlink.</para>
    <option>--requisites</option>.)</para></listitem>

  </varlistentry>
-  
+
  <varlistentry><term><option>--referrers</option></term>
-  
+
    <listitem><para>Prints the set of <emphasis>referrers</emphasis> of
    the store paths <replaceable>paths</replaceable>, that is, the
    store paths currently existing in the Nix store that refer to one
@@ -542,9 +629,9 @@ query is applied to the target of the symlink.</para>
    store paths are added or removed.</para></listitem>

  </varlistentry>
-  
+
  <varlistentry><term><option>--referrers-closure</option></term>
-  
+
    <listitem><para>Prints the closure of the set of store paths
    <replaceable>paths</replaceable> under the referrers relation; that
    is, all store paths that directly or indirectly refer to one of
@@ -555,7 +642,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--deriver</option></term>
-  
+
    <listitem><para>Prints the <link
    linkend="gloss-deriver">deriver</link> of the store paths
    <replaceable>paths</replaceable>.  If the path has no deriver
@@ -566,7 +653,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--graph</option></term>
-  
+
    <listitem><para>Prints the references graph of the store paths
    <replaceable>paths</replaceable> in the format of the
    <command>dot</command> tool of AT&amp;T's <link
@@ -579,7 +666,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--tree</option></term>
-  
+
    <listitem><para>Prints the references graph of the store paths
    <replaceable>paths</replaceable> as a nested ASCII tree.
    References are ordered by descending closure size; this tends to
@@ -591,7 +678,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--binding</option> <replaceable>name</replaceable></term>
-  
+
    <listitem><para>Prints the value of the attribute
    <replaceable>name</replaceable> (i.e., environment variable) of
    the store derivations <replaceable>paths</replaceable>.  It is an
@@ -601,7 +688,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--hash</option></term>
-  
+
    <listitem><para>Prints the SHA-256 hash of the contents of the
    store paths <replaceable>paths</replaceable> (that is, the hash of
    the output of <command>nix-store --dump</command> on the given
@@ -611,7 +698,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--size</option></term>
-  
+
    <listitem><para>Prints the size in bytes of the contents of the
    store paths <replaceable>paths</replaceable> — to be precise, the
    size of the output of <command>nix-store --dump</command> on the
@@ -622,7 +709,7 @@ query is applied to the target of the symlink.</para>
  </varlistentry>

  <varlistentry><term><option>--roots</option></term>
-  
+
    <listitem><para>Prints the garbage collector roots that point,
    directly or indirectly, at the store paths
    <replaceable>paths</replaceable>.</para></listitem>
@@ -638,7 +725,7 @@ query is applied to the target of the symlink.</para>

 <para>Print the closure (runtime dependencies) of the
 <command>svn</command> program in the current user environment:
-    
+
 <screen>
 $ nix-store -qR $(which svn)
 /nix/store/5mbglq5ldqld8sj57273aljwkfvj22mc-subversion-1.1.4
@@ -723,7 +810,7 @@ $ nix-store -q --roots $(which svn)

 </refsection>

-  
+

 <!--######################################################################-->

@@ -739,11 +826,11 @@ $ nix-store -q --roots $(which svn)
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>TODO</para>

 </refsection>
-            
+
 </refsection>
 -->

@@ -798,7 +885,7 @@ $ nix-store --add ./foo.c
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--verify</option> verifies the internal
 consistency of the Nix database, and the consistency between the Nix
 database and the Nix store.  Any inconsistencies encountered are
@@ -811,32 +898,32 @@ in Nix itself.</para>
 <variablelist>

  <varlistentry><term><option>--check-contents</option></term>
-  
+
    <listitem><para>Checks that the contents of every valid store path
    has not been altered by computing a SHA-256 hash of the contents
    and comparing it with the hash stored in the Nix database at build
    time.  Paths that have been modified are printed out.  For large
    stores, <option>--check-contents</option> is obviously quite
    slow.</para></listitem>
-    
+
  </varlistentry>
-  
+
  <varlistentry><term><option>--repair</option></term>
-  
+
    <listitem><para>If any valid path is missing from the store, or
    (if <option>--check-contents</option> is given) the contents of a
    valid path has been modified, then try to repair the path by
    redownloading it.  See <command>nix-store --repair-path</command>
    for details.</para></listitem>
-    
+
  </varlistentry>
-  
+
 </variablelist>

 </para>

 </refsection>
-            
+

 </refsection>

@@ -855,7 +942,7 @@ in Nix itself.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--verify-path</option> compares the
 contents of the given store paths to their cryptographic hashes stored
 in Nix’s database.  For every changed path, it prints a warning
@@ -863,7 +950,7 @@ message.  The exit status is 0 if no path has changed, and 1
 otherwise.</para>

 </refsection>
-            
+
 <refsection><title>Example</title>

 <para>To verify the integrity of the <command>svn</command> command and all its dependencies:
@@ -875,7 +962,7 @@ $ nix-store --verify-path $(nix-store -qR $(which svn))
 </para>

 </refsection>
-            
+
 </refsection>


@@ -893,7 +980,7 @@ $ nix-store --verify-path $(nix-store -qR $(which svn))
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--repair-path</option> attempts to
 “repair” the specified paths by redownloading them using the available
 substituters.  If no substitutes are available, then repair is not
@@ -906,7 +993,7 @@ system may be left in a broken state (e.g., if the path contains a
 critical system component like the GNU C Library).</para></warning>

 </refsection>
-            
+
 <refsection><title>Example</title>

 <screen>
@@ -921,7 +1008,7 @@ fetching path `/nix/store/d7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13'...
 </screen>

 </refsection>
-            
+
 </refsection>


@@ -939,7 +1026,7 @@ fetching path `/nix/store/d7a81wsm1ijwwpkks3725661h3263p5-glibc-2.13'...
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--dump</option> produces a NAR (Nix
 ARchive) file containing the contents of the file system tree rooted
 at <replaceable>path</replaceable>.  The archive is written to
@@ -970,7 +1057,7 @@ links, but not other types of files (such as device nodes).</para>
 --restore</literal>.</para>

 </refsection>
-            
+

 </refsection>

@@ -989,13 +1076,13 @@ links, but not other types of files (such as device nodes).</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--restore</option> unpacks a NAR archive
 to <replaceable>path</replaceable>, which must not already exist.  The
 archive is read from standard input.</para>

 </refsection>
-            
+

 </refsection>

@@ -1014,7 +1101,7 @@ archive is read from standard input.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--export</option> writes a serialisation
 of the specified store paths to standard output in a format that can
 be imported into another Nix store with <command
@@ -1028,20 +1115,20 @@ path).</para>
 <para>This command does not produce a <emphasis>closure</emphasis> of
 the specified paths, so if a store path references other store paths
 that are missing in the target Nix store, the import will fail.  To
-copy a whole closure, do something like
+copy a whole closure, do something like:

 <screen>
 $ nix-store --export $(nix-store -qR <replaceable>paths</replaceable>) > out</screen>

+To import the whole closure again, run:
+
+<screen>
+$ nix-store --import &lt; out</screen>
+
 </para>

-<para>For an example of how <option>--export</option> and
-<option>--import</option> can be used, see the source of the <command
-linkend="sec-nix-copy-closure">nix-copy-closure</command>
-command.</para>
-
 </refsection>
-            
+

 </refsection>

@@ -1059,17 +1146,17 @@ command.</para>
 </refsection>

 <refsection><title>Description</title>
-            
-<para>The operation <option>--export</option> reads a serialisation of
+
+<para>The operation <option>--import</option> reads a serialisation of
 a set of store paths produced by <command
-linkend="refsec-nix-store-export">nix-store --import</command> from
+linkend="refsec-nix-store-export">nix-store --export</command> from
 standard input and adds those store paths to the Nix store.  Paths
 that already exist in the Nix store are ignored.  If a path refers to
 another path that doesn’t exist in the Nix store, the import
 fails.</para>

 </refsection>
-            
+

 </refsection>

@@ -1087,7 +1174,7 @@ fails.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--optimise</option> reduces Nix store disk
 space usage by finding identical files in the store and hard-linking
 them to each other.  It typically reduces the size of the store by
@@ -1104,7 +1191,7 @@ on the achieved savings is printed on standard error.</para>
 progress indication.</para>

 </refsection>
-            
+
 <refsection><title>Example</title>

 <screen>
@@ -1138,7 +1225,7 @@ there are 114486 files with equal contents out of 215894 files in total
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--read-log</option> prints the build log
 of the specified store paths on standard output.  The build log is
 whatever the builder of a derivation wrote to standard output and
@@ -1147,12 +1234,17 @@ the store path is used.</para>

 <para>Build logs are kept in
 <filename>/nix/var/log/nix/drvs</filename>.  However, there is no
-guarantee that a build log is available for any particular store
-path.  For instance, if the path was downloaded as a pre-built binary
-through a substitute, then the log is unavailable.</para>
+guarantee that a build log is available for any particular store path.
+For instance, if the path was downloaded as a pre-built binary through
+a substitute, then the log is unavailable. If the log is not available
+locally, then <command>nix-store</command> will try to download the
+log from the servers specified in the Nix option
+<option>log-servers</option>. For example, if it’s set to
+<literal>http://hydra.nixos.org/log</literal>, then Nix will check
+<literal>http://hydra.nixos.org/log/<replaceable>base-name</replaceable></literal>.</para>

 </refsection>
-            
+
 <refsection><title>Example</title>

 <screen>
@@ -1184,14 +1276,14 @@ ktorrent-2.2.1/NEWS
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--dump-db</option> writes a dump of the
 Nix database to standard output.  It can be loaded into an empty Nix
 store using <option>--load-db</option>.  This is useful for making
 backups and when migrating to different database schemas.</para>

 </refsection>
-            
+
 </refsection>


@@ -1208,13 +1300,13 @@ backups and when migrating to different database schemas.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--load-db</option> reads a dump of the Nix
 database created by <option>--dump-db</option> from standard input and
 loads it into the Nix database.</para>

 </refsection>
-            
+
 </refsection>


@@ -1232,14 +1324,14 @@ loads it into the Nix database.</para>
 </refsection>

 <refsection><title>Description</title>
-            
+
 <para>The operation <option>--print-env</option> prints out the
 environment of a derivation in a format that can be evaluated by a
 shell.  The command line arguments of the builder are placed in the
 variable <envar>_args</envar>.</para>

 </refsection>
-            
+
 <refsection><title>Example</title>

 <screen>
@@ -1252,83 +1344,56 @@ export _args; _args='-e /nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25c-default-buil
 </screen>

 </refsection>
-            
+
 </refsection>


 <!--######################################################################-->

-<refsection><title>Operation <option>--query-failed-paths</option></title>
+<refsection xml:id='rsec-nix-store-generate-binary-cache-key'><title>Operation <option>--generate-binary-cache-key</option></title>

 <refsection>
  <title>Synopsis</title>
  <cmdsynopsis>
    <command>nix-store</command>
-    <arg choice='plain'><option>--query-failed-paths</option></arg>
+    <arg choice='plain'>
+      <option>--generate-binary-cache-key</option>
+      <option>key-name</option>
+      <option>secret-key-file</option>
+      <option>public-key-file</option>
+    </arg>
  </cmdsynopsis>
 </refsection>

 <refsection><title>Description</title>
-            
-<para>If build failure caching is enabled through the
-<literal>build-cache-failures</literal> configuration option, the
-operation <option>--query-failed-paths</option> will print out all
-store paths that have failed to build.</para>
+
+<para>This command generates an <link
+xlink:href="http://ed25519.cr.yp.to/">Ed25519 key pair</link> that can
+be used to create a signed binary cache. It takes three mandatory
+parameters:
+
+<orderedlist>
+
+  <listitem><para>A key name, such as
+  <literal>cache.example.org-1</literal>, that is used to look up keys
+  on the client when it verifies signatures. It can be anything, but
+  it’s suggested to use the host name of your cache
+  (e.g. <literal>cache.example.org</literal>) with a suffix denoting
+  the number of the key (to be incremented every time you need to
+  revoke a key).</para></listitem>
+
+  <listitem><para>The file name where the secret key is to be
+  stored.</para></listitem>
+
+  <listitem><para>The file name where the public key is to be
+  stored.</para></listitem>
+
+</orderedlist>
+
+</para>

 </refsection>
-            
-<refsection><title>Example</title>

-<screen>
-$ nix-store --query-failed-paths
-/nix/store/000zi5dcla86l92jn1g997jb06sidm7x-perl-PerlMagick-6.59
-/nix/store/0011iy7sfwbc1qj5a1f6ifjnbcdail8a-haskell-gitit-ghc7.0.4-0.8.1
-/nix/store/001c0yn1hkh86gprvrb46cxnz3pki7q3-gamin-0.1.10
-<replaceable>…</replaceable>
-</screen>
-
-</refsection>
-            
-</refsection>
-
-
-<!--######################################################################-->
-
-<refsection><title>Operation <option>--clear-failed-paths</option></title>
-
-<refsection>
-  <title>Synopsis</title>
-  <cmdsynopsis>
-    <command>nix-store</command>
-    <arg choice='plain'><option>--clear-failed-paths</option></arg>
-    <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
-  </cmdsynopsis>
-</refsection>
-
-<refsection><title>Description</title>
-            
-<para>If build failure caching is enabled through the
-<literal>build-cache-failures</literal> configuration option, the
-operation <option>--clear-failed-paths</option> clears the “failed”
-state of the given store paths, allowing them to be built again.  This
-is useful if the failure was actually transient (e.g. because the disk
-was full).</para>
-
-<para>If a path denotes a derivation, its output paths are cleared.
-You can provide the argument <literal>*</literal> to clear all store
-paths.</para>
-
-</refsection>
-            
-<refsection><title>Example</title>
-
-<screen>
-$ nix-store --clear-failed-paths /nix/store/000zi5dcla86l92jn1g997jb06sidm7x-perl-PerlMagick-6.59
-$ nix-store --clear-failed-paths *
-</screen>
-
-</refsection>
-            
 </refsection>


@@ -1341,6 +1406,6 @@ $ nix-store --clear-failed-paths *
 </variablelist>

 </refsection>
-  
+

 </refentry>
@@ -31,7 +31,6 @@
 <arg><option>-K</option></arg>
 <arg><option>--fallback</option></arg>
 <arg><option>--readonly-mode</option></arg>
-<arg><option>--log-type</option> <replaceable>type</replaceable></arg>
 <arg><option>--show-trace</option></arg>
 <arg>
  <option>-I</option>
@@ -1,6 +1,6 @@
-<section xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options">
+<chapter xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options">

-<title>Common options</title>
+<title>Common Options</title>


 <para>Most Nix commands accept the following command-line options:</para>
@@ -191,6 +191,23 @@

 </varlistentry>

+<varlistentry><term><option>--no-build-hook</option></term>
+
+  <listitem>
+
+  <para>Disables the build hook mechanism.  This allows to ignore remote
+  builders if they are setup on the machine.</para>
+
+  <para>It's useful in cases where the bandwidth between the client and the
+  remote builder is too low.  In that case it can take more time to upload the
+  sources to the remote builder and fetch back the result than to do the
+  computation locally.</para>
+
+  </listitem>
+
+</varlistentry>
+
+

 <varlistentry><term><option>--readonly-mode</option></term>

@@ -201,61 +218,6 @@
 </varlistentry>


-<varlistentry xml:id="opt-log-type"><term><option>--log-type</option>
-<replaceable>type</replaceable></term>
-
-  <listitem>
-
-  <para>This option determines how the output written to standard
-  error is formatted.  Nix’s diagnostic messages are typically
-  <emphasis>nested</emphasis>.  For instance, when tracing Nix
-  expression evaluation (<command>nix-env -vvvvv</command>, messages
-  from subexpressions are nested inside their parent expressions.  Nix
-  builder output is also often nested.  For instance, the Nix Packages
-  generic builder nests the various build tasks (unpack, configure,
-  compile, etc.), and the GNU Make in <literal>stdenv-linux</literal>
-  has been patched to provide nesting for recursive Make
-  invocations.</para>
-
-  <para><replaceable>type</replaceable> can be one of the
-  following:
-
-  <variablelist>
-
-    <varlistentry><term><literal>pretty</literal></term>
-
-      <listitem><para>Pretty-print the output, indicating different
-      nesting levels using spaces.  This is the
-      default.</para></listitem>
-
-    </varlistentry>
-
-    <varlistentry><term><literal>escapes</literal></term>
-
-      <listitem><para>Indicate nesting using escape codes that can be
-      interpreted by the <command>nix-log2xml</command> tool in the
-      Nix source distribution.  The resulting XML file can be fed into
-      the <command>log2html.xsl</command> stylesheet to create an HTML
-      file that can be browsed interactively, using JavaScript to
-      expand and collapse parts of the output.</para></listitem>
-
-    </varlistentry>
-
-    <varlistentry><term><literal>flat</literal></term>
-
-      <listitem><para>Remove all nesting.</para></listitem>
-
-    </varlistentry>
-
-  </variablelist>
-
-  </para>
-
-  </listitem>
-
-</varlistentry>
-
-
 <varlistentry><term><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term>

  <listitem><para>This option is accepted by
@@ -273,9 +235,8 @@
  named <replaceable>name</replaceable>, it will call it with value
  <replaceable>value</replaceable>.</para>

-  <para>For instance, the file
-  <literal>pkgs/top-level/all-packages.nix</literal> in Nixpkgs is
-  actually a function:
+  <para>For instance, the top-level <literal>default.nix</literal> in
+  Nixpkgs is actually a function:

 <programlisting>
 { # The system (e.g., `i686-linux') for which to build the packages.
@@ -351,13 +312,14 @@
 </varlistentry>


-<varlistentry><term><option>-I</option> <replaceable>path</replaceable></term>
+<varlistentry xml:id="opt-I"><term><option>-I</option> <replaceable>path</replaceable></term>

  <listitem><para>Add a path to the Nix expression search path.  This
-  option may be given multiple times.  See the <envar>NIX_PATH</envar>
-  environment variable for information on the semantics of the Nix
-  search path.  Paths added through <option>-I</option> take
-  precedence over <envar>NIX_PATH</envar>.</para></listitem>
+  option may be given multiple times.  See the <envar
+  linkend="env-NIX_PATH">NIX_PATH</envar> environment variable for
+  information on the semantics of the Nix search path.  Paths added
+  through <option>-I</option> take precedence over
+  <envar>NIX_PATH</envar>.</para></listitem>

 </varlistentry>

@@ -386,4 +348,4 @@
 </variablelist>


-</section>
+</chapter>
@@ -0,0 +1,20 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='ch-utilities'>
+
+<title>Utilities</title>
+
+<para>This section lists utilities that you can use when you
+work with Nix.</para>
+
+<xi:include href="nix-channel.xml" />
+<xi:include href="nix-collect-garbage.xml" />
+<xi:include href="nix-copy-closure.xml" />
+<xi:include href="nix-daemon.xml" />
+<xi:include href="nix-hash.xml" />
+<xi:include href="nix-instantiate.xml" />
+<xi:include href="nix-prefetch-url.xml" />
+
+</chapter>
@@ -0,0 +1,289 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-advanced-attributes">
+
+<title>Advanced Attributes</title>
+
+<para>Derivations can declare some infrequently used optional
+attributes.</para>
+
+<variablelist>
+
+  <varlistentry><term><varname>allowedReferences</varname></term>
+
+    <listitem><para>The optional attribute
+    <varname>allowedReferences</varname> specifies a list of legal
+    references (dependencies) of the output of the builder.  For
+    example,
+
+<programlisting>
+allowedReferences = [];
+</programlisting>
+
+    enforces that the output of a derivation cannot have any runtime
+    dependencies on its inputs.  To allow an output to have a runtime
+    dependency on itself, use <literal>"out"</literal> as a list item.
+    This is used in NixOS to check that generated files such as
+    initial ramdisks for booting Linux don’t have accidental
+    dependencies on other paths in the Nix store.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><varname>allowedRequisites</varname></term>
+
+    <listitem><para>This attribute is similar to
+    <varname>allowedReferences</varname>, but it specifies the legal
+    requisites of the whole closure, so all the dependencies
+    recursively.  For example,
+
+<programlisting>
+allowedRequisites = [ foobar ];
+</programlisting>
+
+    enforces that the output of a derivation cannot have any other
+    runtime dependency than <varname>foobar</varname>, and in addition
+    it enforces that <varname>foobar</varname> itself doesn't
+    introduce any other dependency itself.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><varname>exportReferencesGraph</varname></term>
+
+    <listitem><para>This attribute allows builders access to the
+    references graph of their inputs.  The attribute is a list of
+    inputs in the Nix store whose references graph the builder needs
+    to know.  The value of this attribute should be a list of pairs
+    <literal>[ <replaceable>name1</replaceable>
+    <replaceable>path1</replaceable> <replaceable>name2</replaceable>
+    <replaceable>path2</replaceable> <replaceable>...</replaceable>
+    ]</literal>.  The references graph of each
+    <replaceable>pathN</replaceable> will be stored in a text file
+    <replaceable>nameN</replaceable> in the temporary build directory.
+    The text files have the format used by <command>nix-store
+    --register-validity</command> (with the deriver fields left
+    empty).  For example, when the following derivation is built:
+
+<programlisting>
+derivation {
+  ...
+  exportReferencesGraph = [ "libfoo-graph" libfoo ];
+};
+</programlisting>
+
+    the references graph of <literal>libfoo</literal> is placed in the
+    file <filename>libfoo-graph</filename> in the temporary build
+    directory.</para>
+
+    <para><varname>exportReferencesGraph</varname> is useful for
+    builders that want to do something with the closure of a store
+    path.  Examples include the builders in NixOS that generate the
+    initial ramdisk for booting Linux (a <command>cpio</command>
+    archive containing the closure of the boot script) and the
+    ISO-9660 image for the installation CD (which is populated with a
+    Nix store containing the closure of a bootable NixOS
+    configuration).</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><varname>impureEnvVars</varname></term>
+
+    <listitem><para>This attribute allows you to specify a list of
+    environment variables that should be passed from the environment
+    of the calling user to the builder.  Usually, the environment is
+    cleared completely when the builder is executed, but with this
+    attribute you can allow specific environment variables to be
+    passed unmodified.  For example, <function>fetchurl</function> in
+    Nixpkgs has the line
+
+<programlisting>
+impureEnvVars = [ "http_proxy" "https_proxy" <replaceable>...</replaceable> ];
+</programlisting>
+
+    to make it use the proxy server configuration specified by the
+    user in the environment variables <envar>http_proxy</envar> and
+    friends.</para>
+
+    <para>This attribute is only allowed in <link
+    linkend="fixed-output-drvs">fixed-output derivations</link>, where
+    impurities such as these are okay since (the hash of) the output
+    is known in advance.  It is ignored for all other
+    derivations.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry xml:id="fixed-output-drvs">
+    <term><varname>outputHash</varname></term>
+    <term><varname>outputHashAlgo</varname></term>
+    <term><varname>outputHashMode</varname></term>
+
+    <listitem><para>These attributes declare that the derivation is a
+    so-called <emphasis>fixed-output derivation</emphasis>, which
+    means that a cryptographic hash of the output is already known in
+    advance.  When the build of a fixed-output derivation finishes,
+    Nix computes the cryptographic hash of the output and compares it
+    to the hash declared with these attributes.  If there is a
+    mismatch, the build fails.</para>
+
+    <para>The rationale for fixed-output derivations is derivations
+    such as those produced by the <function>fetchurl</function>
+    function.  This function downloads a file from a given URL.  To
+    ensure that the downloaded file has not been modified, the caller
+    must also specify a cryptographic hash of the file.  For example,
+
+<programlisting>
+fetchurl {
+  url = http://ftp.gnu.org/pub/gnu/hello/hello-2.1.1.tar.gz;
+  md5 = "70c9ccf9fac07f762c24f2df2290784d";
+}
+</programlisting>
+
+    It sometimes happens that the URL of the file changes, e.g.,
+    because servers are reorganised or no longer available.  We then
+    must update the call to <function>fetchurl</function>, e.g.,
+
+<programlisting>
+fetchurl {
+  url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz;
+  md5 = "70c9ccf9fac07f762c24f2df2290784d";
+}
+</programlisting>
+
+    If a <function>fetchurl</function> derivation was treated like a
+    normal derivation, the output paths of the derivation and
+    <emphasis>all derivations depending on it</emphasis> would change.
+    For instance, if we were to change the URL of the Glibc source
+    distribution in Nixpkgs (a package on which almost all other
+    packages depend) massive rebuilds would be needed.  This is
+    unfortunate for a change which we know cannot have a real effect
+    as it propagates upwards through the dependency graph.</para>
+
+    <para>For fixed-output derivations, on the other hand, the name of
+    the output path only depends on the <varname>outputHash*</varname>
+    and <varname>name</varname> attributes, while all other attributes
+    are ignored for the purpose of computing the output path.  (The
+    <varname>name</varname> attribute is included because it is part
+    of the path.)</para>
+
+    <para>As an example, here is the (simplified) Nix expression for
+    <varname>fetchurl</varname>:
+
+<programlisting>
+{ stdenv, curl }: # The <command>curl</command> program is used for downloading.
+
+{ url, md5 }:
+
+stdenv.mkDerivation {
+  name = baseNameOf (toString url);
+  builder = ./builder.sh;
+  buildInputs = [ curl ];
+
+  # This is a fixed-output derivation; the output must be a regular
+  # file with MD5 hash <varname>md5</varname>.
+  outputHashMode = "flat";
+  outputHashAlgo = "md5";
+  outputHash = md5;
+
+  inherit url;
+}
+</programlisting>
+
+    </para>
+
+    <para>The <varname>outputHashAlgo</varname> attribute specifies
+    the hash algorithm used to compute the hash.  It can currently be
+    <literal>"md5"</literal>, <literal>"sha1"</literal> or
+    <literal>"sha256"</literal>.</para>
+
+    <para>The <varname>outputHashMode</varname> attribute determines
+    how the hash is computed.  It must be one of the following two
+    values:
+
+    <variablelist>
+
+      <varlistentry><term><literal>"flat"</literal></term>
+
+        <listitem><para>The output must be a non-executable regular
+        file.  If it isn’t, the build fails.  The hash is simply
+        computed over the contents of that file (so it’s equal to what
+        Unix commands like <command>md5sum</command> or
+        <command>sha1sum</command> produce).</para>
+
+        <para>This is the default.</para></listitem>
+
+      </varlistentry>
+
+      <varlistentry><term><literal>"recursive"</literal></term>
+
+        <listitem><para>The hash is computed over the NAR archive dump
+        of the output (i.e., the result of <link
+        linkend="refsec-nix-store-dump"><command>nix-store
+        --dump</command></link>).  In this case, the output can be
+        anything, including a directory tree.</para></listitem>
+
+      </varlistentry>
+
+    </variablelist>
+
+    </para>
+
+    <para>The <varname>outputHash</varname> attribute, finally, must
+    be a string containing the hash in either hexadecimal or base-32
+    notation.  (See the <link
+    linkend="sec-nix-hash"><command>nix-hash</command> command</link>
+    for information about converting to and from base-32
+    notation.)</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><varname>passAsFile</varname></term>
+
+    <listitem><para>A list of names of attributes that should be
+    passed via files rather than environment variables.  For example,
+    if you have
+
+    <programlisting>
+passAsFile = ["big"];
+big = "a very long string";
+    </programlisting>
+
+    then when the builder runs, the environment variable
+    <envar>bigPath</envar> will contain the absolute path to a
+    temporary file containing <literal>a very long
+    string</literal>. That is, for any attribute
+    <replaceable>x</replaceable> listed in
+    <varname>passAsFile</varname>, Nix will pass an environment
+    variable <envar><replaceable>x</replaceable>Path</envar> holding
+    the path of the file containing the value of attribute
+    <replaceable>x</replaceable>. This is useful when you need to pass
+    large strings to a builder, since most operating systems impose a
+    limit on the size of the environment (typically, a few hundred
+    kilobyte).</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><varname>preferLocalBuild</varname></term>
+
+    <listitem><para>If this attribute is set to
+    <literal>true</literal>, it has two effects.  First, the
+    derivation will always be built, not substituted, even if a
+    substitute is available.  Second, if <link
+    linkend="chap-distributed-builds">distributed building is
+    enabled</link>, then, if possible, the derivaton will be built
+    locally instead of forwarded to a remote machine.  This is
+    appropriate for trivial builders where the cost of doing a
+    download or remote build would exceed the cost of building
+    locally.</para></listitem>
+
+  </varlistentry>
+
+</variablelist>
+
+</section>
@@ -0,0 +1,121 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-arguments'>
+
+<title>Arguments and Variables</title>
+
+<example xml:id='ex-hello-composition'>
+
+<title>Composing GNU Hello
+(<filename>all-packages.nix</filename>)</title>
+<programlisting>
+...
+
+rec { <co xml:id='ex-hello-composition-co-1' />
+
+  hello = import ../applications/misc/hello/ex-1 <co xml:id='ex-hello-composition-co-2' /> { <co xml:id='ex-hello-composition-co-3' />
+    inherit fetchurl stdenv perl;
+  };
+
+  perl = import ../development/interpreters/perl { <co xml:id='ex-hello-composition-co-4' />
+    inherit fetchurl stdenv;
+  };
+
+  fetchurl = import ../build-support/fetchurl {
+    inherit stdenv; ...
+  };
+
+  stdenv = ...;
+
+}
+</programlisting>
+</example>
+
+<para>The Nix expression in <xref linkend='ex-hello-nix' /> is a
+function; it is missing some arguments that have to be filled in
+somewhere.  In the Nix Packages collection this is done in the file
+<filename>pkgs/top-level/all-packages.nix</filename>, where all
+Nix expressions for packages are imported and called with the
+appropriate arguments.  <xref linkend='ex-hello-composition' /> shows
+some fragments of
+<filename>all-packages.nix</filename>.</para>
+
+<calloutlist>
+
+  <callout arearefs='ex-hello-composition-co-1'>
+
+    <para>This file defines a set of attributes, all of which are
+    concrete derivations (i.e., not functions).  In fact, we define a
+    <emphasis>mutually recursive</emphasis> set of attributes.  That
+    is, the attributes can refer to each other.  This is precisely
+    what we want since we want to <quote>plug</quote> the
+    various packages into each other.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-composition-co-2'>
+
+    <para>Here we <emphasis>import</emphasis> the Nix expression for
+    GNU Hello.  The import operation just loads and returns the
+    specified Nix expression. In fact, we could just have put the
+    contents of <xref linkend='ex-hello-nix' /> in
+    <filename>all-packages.nix</filename> at this point.  That
+    would be completely equivalent, but it would make the file rather
+    bulky.</para>
+
+    <para>Note that we refer to
+    <filename>../applications/misc/hello/ex-1</filename>, not
+    <filename>../applications/misc/hello/ex-1/default.nix</filename>.
+    When you try to import a directory, Nix automatically appends
+    <filename>/default.nix</filename> to the file name.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-composition-co-3'>
+
+    <para>This is where the actual composition takes place.  Here we
+    <emphasis>call</emphasis> the function imported from
+    <filename>../applications/misc/hello/ex-1</filename> with a set
+    containing the things that the function expects, namely
+    <varname>fetchurl</varname>, <varname>stdenv</varname>, and
+    <varname>perl</varname>.  We use inherit again to use the
+    attributes defined in the surrounding scope (we could also have
+    written <literal>fetchurl = fetchurl;</literal>, etc.).</para>
+
+    <para>The result of this function call is an actual derivation
+    that can be built by Nix (since when we fill in the arguments of
+    the function, what we get is its body, which is the call to
+    <varname>stdenv.mkDerivation</varname> in <xref
+    linkend='ex-hello-nix' />).</para>
+
+    <note><para>Nixpkgs has a convenience function
+    <function>callPackage</function> that imports and calls a
+    function, filling in any missing arguments by passing the
+    corresponding attribute from the Nixpkgs set, like this:
+
+<programlisting>
+hello = callPackage ../applications/misc/hello/ex-1 { };
+</programlisting>
+
+    If necessary, you can set or override arguments:
+
+<programlisting>
+hello = callPackage ../applications/misc/hello/ex-1 { stdenv = myStdenv; };
+</programlisting>
+
+    </para></note>
+
+  </callout>
+
+  <callout arearefs='ex-hello-composition-co-4'>
+
+    <para>Likewise, we have to instantiate Perl,
+    <varname>fetchurl</varname>, and the standard environment.</para>
+
+  </callout>
+
+</calloutlist>
+
+</section>
@@ -0,0 +1,119 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-build-script'>
+
+<title>Build Script</title>
+
+<example xml:id='ex-hello-builder'><title>Build script for GNU Hello
+(<filename>builder.sh</filename>)</title>
+<programlisting>
+source $stdenv/setup <co xml:id='ex-hello-builder-co-1' />
+
+PATH=$perl/bin:$PATH <co xml:id='ex-hello-builder-co-2' />
+
+tar xvfz $src <co xml:id='ex-hello-builder-co-3' />
+cd hello-*
+./configure --prefix=$out <co xml:id='ex-hello-builder-co-4' />
+make <co xml:id='ex-hello-builder-co-5' />
+make install</programlisting>
+</example>
+
+<para><xref linkend='ex-hello-builder' /> shows the builder referenced
+from Hello's Nix expression (stored in
+<filename>pkgs/applications/misc/hello/ex-1/builder.sh</filename>).
+The builder can actually be made a lot shorter by using the
+<emphasis>generic builder</emphasis> functions provided by
+<varname>stdenv</varname>, but here we write out the build steps to
+elucidate what a builder does.  It performs the following
+steps:</para>
+
+<calloutlist>
+
+  <callout arearefs='ex-hello-builder-co-1'>
+
+    <para>When Nix runs a builder, it initially completely clears the
+    environment (except for the attributes declared in the
+    derivation).  For instance, the <envar>PATH</envar> variable is
+    empty<footnote><para>Actually, it's initialised to
+    <filename>/path-not-set</filename> to prevent Bash from setting it
+    to a default value.</para></footnote>.  This is done to prevent
+    undeclared inputs from being used in the build process.  If for
+    example the <envar>PATH</envar> contained
+    <filename>/usr/bin</filename>, then you might accidentally use
+    <filename>/usr/bin/gcc</filename>.</para>
+
+    <para>So the first step is to set up the environment.  This is
+    done by calling the <filename>setup</filename> script of the
+    standard environment.  The environment variable
+    <envar>stdenv</envar> points to the location of the standard
+    environment being used.  (It wasn't specified explicitly as an
+    attribute in <xref linkend='ex-hello-nix' />, but
+    <varname>mkDerivation</varname> adds it automatically.)</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-2'>
+
+    <para>Since Hello needs Perl, we have to make sure that Perl is in
+    the <envar>PATH</envar>.  The <envar>perl</envar> environment
+    variable points to the location of the Perl package (since it
+    was passed in as an attribute to the derivation), so
+    <filename><replaceable>$perl</replaceable>/bin</filename> is the
+    directory containing the Perl interpreter.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-3'>
+
+    <para>Now we have to unpack the sources.  The
+    <varname>src</varname> attribute was bound to the result of
+    fetching the Hello source tarball from the network, so the
+    <envar>src</envar> environment variable points to the location in
+    the Nix store to which the tarball was downloaded.  After
+    unpacking, we <command>cd</command> to the resulting source
+    directory.</para>
+
+    <para>The whole build is performed in a temporary directory
+    created in <varname>/tmp</varname>, by the way.  This directory is
+    removed after the builder finishes, so there is no need to clean
+    up the sources afterwards.  Also, the temporary directory is
+    always newly created, so you don't have to worry about files from
+    previous builds interfering with the current build.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-4'>
+
+    <para>GNU Hello is a typical Autoconf-based package, so we first
+    have to run its <filename>configure</filename> script.  In Nix
+    every package is stored in a separate location in the Nix store,
+    for instance
+    <filename>/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1</filename>.
+    Nix computes this path by cryptographically hashing all attributes
+    of the derivation.  The path is passed to the builder through the
+    <envar>out</envar> environment variable.  So here we give
+    <filename>configure</filename> the parameter
+    <literal>--prefix=$out</literal> to cause Hello to be installed in
+    the expected location.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-5'>
+
+    <para>Finally we build Hello (<literal>make</literal>) and install
+    it into the location specified by <envar>out</envar>
+    (<literal>make install</literal>).</para>
+
+  </callout>
+
+</calloutlist>
+
+<para>If you are wondering about the absence of error checking on the
+result of various commands called in the builder: this is because the
+shell script is evaluated with Bash's <option>-e</option> option,
+which causes the script to be aborted if any command fails without an
+error check.</para>
+
+</section>
@@ -0,0 +1,119 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-builder-syntax'>
+
+<title>Builder Syntax</title>
+
+<example xml:id='ex-hello-builder'><title>Build script for GNU Hello
+(<filename>builder.sh</filename>)</title>
+<programlisting>
+source $stdenv/setup <co xml:id='ex-hello-builder-co-1' />
+
+PATH=$perl/bin:$PATH <co xml:id='ex-hello-builder-co-2' />
+
+tar xvfz $src <co xml:id='ex-hello-builder-co-3' />
+cd hello-*
+./configure --prefix=$out <co xml:id='ex-hello-builder-co-4' />
+make <co xml:id='ex-hello-builder-co-5' />
+make install</programlisting>
+</example>
+
+<para><xref linkend='ex-hello-builder' /> shows the builder referenced
+from Hello's Nix expression (stored in
+<filename>pkgs/applications/misc/hello/ex-1/builder.sh</filename>).
+The builder can actually be made a lot shorter by using the
+<emphasis>generic builder</emphasis> functions provided by
+<varname>stdenv</varname>, but here we write out the build steps to
+elucidate what a builder does.  It performs the following
+steps:</para>
+
+<calloutlist>
+
+  <callout arearefs='ex-hello-builder-co-1'>
+
+    <para>When Nix runs a builder, it initially completely clears the
+    environment (except for the attributes declared in the
+    derivation).  For instance, the <envar>PATH</envar> variable is
+    empty<footnote><para>Actually, it's initialised to
+    <filename>/path-not-set</filename> to prevent Bash from setting it
+    to a default value.</para></footnote>.  This is done to prevent
+    undeclared inputs from being used in the build process.  If for
+    example the <envar>PATH</envar> contained
+    <filename>/usr/bin</filename>, then you might accidentally use
+    <filename>/usr/bin/gcc</filename>.</para>
+
+    <para>So the first step is to set up the environment.  This is
+    done by calling the <filename>setup</filename> script of the
+    standard environment.  The environment variable
+    <envar>stdenv</envar> points to the location of the standard
+    environment being used.  (It wasn't specified explicitly as an
+    attribute in <xref linkend='ex-hello-nix' />, but
+    <varname>mkDerivation</varname> adds it automatically.)</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-2'>
+
+    <para>Since Hello needs Perl, we have to make sure that Perl is in
+    the <envar>PATH</envar>.  The <envar>perl</envar> environment
+    variable points to the location of the Perl package (since it
+    was passed in as an attribute to the derivation), so
+    <filename><replaceable>$perl</replaceable>/bin</filename> is the
+    directory containing the Perl interpreter.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-3'>
+
+    <para>Now we have to unpack the sources.  The
+    <varname>src</varname> attribute was bound to the result of
+    fetching the Hello source tarball from the network, so the
+    <envar>src</envar> environment variable points to the location in
+    the Nix store to which the tarball was downloaded.  After
+    unpacking, we <command>cd</command> to the resulting source
+    directory.</para>
+
+    <para>The whole build is performed in a temporary directory
+    created in <varname>/tmp</varname>, by the way.  This directory is
+    removed after the builder finishes, so there is no need to clean
+    up the sources afterwards.  Also, the temporary directory is
+    always newly created, so you don't have to worry about files from
+    previous builds interfering with the current build.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-4'>
+
+    <para>GNU Hello is a typical Autoconf-based package, so we first
+    have to run its <filename>configure</filename> script.  In Nix
+    every package is stored in a separate location in the Nix store,
+    for instance
+    <filename>/nix/store/9a54ba97fb71b65fda531012d0443ce2-hello-2.1.1</filename>.
+    Nix computes this path by cryptographically hashing all attributes
+    of the derivation.  The path is passed to the builder through the
+    <envar>out</envar> environment variable.  So here we give
+    <filename>configure</filename> the parameter
+    <literal>--prefix=$out</literal> to cause Hello to be installed in
+    the expected location.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder-co-5'>
+
+    <para>Finally we build Hello (<literal>make</literal>) and install
+    it into the location specified by <envar>out</envar>
+    (<literal>make install</literal>).</para>
+
+  </callout>
+
+</calloutlist>
+
+<para>If you are wondering about the absence of error checking on the
+result of various commands called in the builder: this is because the
+shell script is evaluated with Bash's <option>-e</option> option,
+which causes the script to be aborted if any command fails without an
+error check.</para>
+
+</section>
@@ -1,9 +1,10 @@
 <section xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id='ssec-builtins'>
-
-<title>Built-in functions</title>
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='ssec-builtins'>

+<title>Built-in Functions</title>

 <para>This section lists the functions and constants built into the
 Nix expression evaluator.  (The built-in function
@@ -31,27 +32,52 @@ available as <function>builtins.derivation</function>.</para>
  <varlistentry><term><function>builtins.add</function>
  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>

-    <listitem><para>Return the sum of the integers
+    <listitem><para>Return the sum of the numbers
    <replaceable>e1</replaceable> and
    <replaceable>e2</replaceable>.</para></listitem>

  </varlistentry>


+  <varlistentry><term><function>builtins.all</function>
+  <replaceable>pred</replaceable> <replaceable>list</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if the function
+    <replaceable>pred</replaceable> returns <literal>true</literal>
+    for all elements of <replaceable>list</replaceable>,
+    and <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.any</function>
+  <replaceable>pred</replaceable> <replaceable>list</replaceable></term>
+
+    <listitem><para>Return <literal>true</literal> if the function
+    <replaceable>pred</replaceable> returns <literal>true</literal>
+    for at least one element of <replaceable>list</replaceable>,
+    and <literal>false</literal> otherwise.</para></listitem>
+
+  </varlistentry>
+
+
  <varlistentry><term><function>builtins.attrNames</function>
  <replaceable>set</replaceable></term>

    <listitem><para>Return the names of the attributes in the set
    <replaceable>set</replaceable> in a sorted list.  For instance,
    <literal>builtins.attrNames { y = 1; x = "foo"; }</literal>
-    evaluates to <literal>[ "x" "y" ]</literal>.  There is no built-in
-    function <function>attrValues</function>, but you can easily
-    define it yourself:
+    evaluates to <literal>[ "x" "y" ]</literal>.</para></listitem>

-<programlisting>
-attrValues = set: map (name: builtins.getAttr name set) (builtins.attrNames set);</programlisting>
+  </varlistentry>

-    </para></listitem>
+
+  <varlistentry><term><function>builtins.attrValues</function>
+  <replaceable>set</replaceable></term>
+
+    <listitem><para>Return the values of the attributes in the set
+    <replaceable>set</replaceable> in the order corresponding to the
+    sorted attribute names.</para></listitem>

  </varlistentry>

@@ -116,7 +142,7 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
    evaluates to the Nix platform identifier for the Nix installation
    on which the expression is being evaluated, such as
    <literal>"i686-linux"</literal> or
-    <literal>"powerpc-darwin"</literal>.</para></listitem>
+    <literal>"x86_64-darwin"</literal>.</para></listitem>

  </varlistentry>

@@ -143,6 +169,19 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
  -->


+  <varlistentry><term><function>builtins.deepSeq</function>
+  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
+
+    <listitem><para>This is like <literal>seq
+    <replaceable>e1</replaceable>
+    <replaceable>e2</replaceable></literal>, except that
+    <replaceable>e1</replaceable> is evaluated
+    <emphasis>deeply</emphasis>: if it’s a list or set, its elements
+    or attributes are also evaluated recursively.</para></listitem>
+
+  </varlistentry>
+
+
  <varlistentry><term><function>derivation</function>
  <replaceable>attrs</replaceable></term>

@@ -165,12 +204,41 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
  <varlistentry><term><function>builtins.div</function>
  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>

-    <listitem><para>Return the quotient of the integers
+    <listitem><para>Return the quotient of the numbers
    <replaceable>e1</replaceable> and
    <replaceable>e2</replaceable>.</para></listitem>

  </varlistentry>

+  <varlistentry><term><function>builtins.match</function>
+  <replaceable>regex</replaceable> <replaceable>str</replaceable></term>
+
+  <listitem><para>Returns a list if
+    <replaceable>regex</replaceable> matches
+    <replaceable>str</replaceable> precisely, otherwise returns <literal>null</literal>.
+    Each item in the list is a regex group.
+
+<programlisting>
+builtins.match "ab" "abc"
+</programlisting>
+
+Evaluates to <literal>null</literal>.
+
+<programlisting>
+builtins.match "abc" "abc"
+</programlisting>
+
+Evaluates to <literal>[ ]</literal>.
+
+<programlisting>
+builtins.match "a(b)(c)" "abc"
+</programlisting>
+
+Evaluates to <literal>[ "b" "c" ]</literal>.
+
+
+  </para></listitem>
+  </varlistentry>

  <varlistentry><term><function>builtins.elem</function>
  <replaceable>x</replaceable> <replaceable>xs</replaceable></term>
@@ -194,6 +262,45 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
  </varlistentry>


+  <varlistentry><term><function>builtins.fetchurl</function>
+  <replaceable>url</replaceable></term>
+
+    <listitem><para>Download the specified URL and return the path of
+    the downloaded file. This function is not available if <link
+    linkend="conf-restrict-eval">restricted evaluation mode</link> is
+    enabled.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>fetchTarball</function>
+  <replaceable>url</replaceable></term>
+
+    <listitem><para>Download the specified URL, unpack it and return
+    the path of the unpacked tree. The file must be a tape archive
+    (<filename>.tar</filename>) compressed with
+    <literal>gzip</literal>, <literal>bzip2</literal> or
+    <literal>xz</literal>. The top-level path component of the files
+    in the tarball is removed, so it is best if the tarball contains a
+    single directory at top level. The typical use of the function is
+    to obtain external Nix expression dependencies, such as a
+    particular version of Nixpkgs, e.g.
+
+<programlisting>
+with import (fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-14.12.tar.gz) {};
+
+stdenv.mkDerivation { … }
+</programlisting>
+
+    </para>
+
+    <para>This function is not available if <link
+    linkend="conf-restrict-eval">restricted evaluation mode</link> is
+    enabled.</para></listitem>
+
+  </varlistentry>
+
+
  <varlistentry><term><function>builtins.filter</function>
  <replaceable>f</replaceable> <replaceable>xs</replaceable></term>

@@ -257,6 +364,71 @@ stdenv.mkDerivation {
  </varlistentry>


+  <varlistentry><term><function>builtins.foldl’</function>
+    <replaceable>op</replaceable> <replaceable>nul</replaceable> <replaceable>list</replaceable></term>
+
+    <listitem><para>Reduce a list by applying a binary operator, from
+    left to right, e.g. <literal>foldl’ op nul [x0 x1 x2 ...] = op (op
+    (op nul x0) x1) x2) ...</literal>. The operator is applied
+    strictly, i.e., its arguments are evaluated first. For example,
+    <literal>foldl’ (x: y: x + y) 0 [1 2 3]</literal> evaluates to
+    6.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.functionArgs</function>
+    <replaceable>f</replaceable></term>
+
+    <listitem><para>
+    Return a set containing the names of the formal arguments expected
+    by the function <replaceable>f</replaceable>.
+    The value of each attribute is a Boolean denoting whether the corresponding
+    argument has a default value.  For instance,
+    <literal>functionArgs ({ x, y ? 123}: ...)  =  { x = false; y = true; }</literal>.
+    </para>
+
+    <para>"Formal argument" here refers to the attributes pattern-matched by
+    the function.  Plain lambdas are not included, e.g.
+    <literal>functionArgs (x: ...)  =  { }</literal>.
+    </para></listitem>
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.fromJSON</function> <replaceable>e</replaceable></term>
+
+    <listitem><para>Convert a JSON string to a Nix
+    value. For example,
+
+<programlisting>
+builtins.fromJSON ''{"x": [1, 2, 3], "y": null}''
+</programlisting>
+
+    returns the value <literal>{ x = [ 1 2 3 ]; y = null;
+    }</literal>. Floating point numbers are not
+    supported.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.genList</function>
+  <replaceable>generator</replaceable> <replaceable>length</replaceable></term>
+
+    <listitem><para>Generate list of size
+    <replaceable>length</replaceable>, with each element
+    <replaceable>i></replaceable> equal to the value returned by
+    <replaceable>generator</replaceable> <literal>i</literal>. For
+    example,
+
+<programlisting>
+builtins.genList (x: x * x) 5
+</programlisting>
+
+    returns the list <literal>[ 0 1 4 9 16 ]</literal>.</para></listitem>
+
+  </varlistentry>
+
+
  <varlistentry><term><function>builtins.getAttr</function>
  <replaceable>s</replaceable> <replaceable>set</replaceable></term>

@@ -477,12 +649,12 @@ x: x + 456</programlisting>
  <varlistentry><term><function>builtins.lessThan</function>
  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>

-    <listitem><para>Return <literal>true</literal> if the integer
-    <replaceable>e1</replaceable> is less than the integer
+    <listitem><para>Return <literal>true</literal> if the number
+    <replaceable>e1</replaceable> is less than the number
    <replaceable>e2</replaceable>, and <literal>false</literal>
    otherwise.  Evaluation aborts if either
    <replaceable>e1</replaceable> or <replaceable>e2</replaceable>
-    does not evaluate to an integer.</para></listitem>
+    does not evaluate to a number.</para></listitem>

  </varlistentry>

@@ -533,7 +705,7 @@ map (x: "foo" + x) [ "bar" "bla" "abc" ]</programlisting>
  <varlistentry><term><function>builtins.mul</function>
  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>

-    <listitem><para>Return the product of the integers
+    <listitem><para>Return the product of the numbers
    <replaceable>e1</replaceable> and
    <replaceable>e2</replaceable>.</para></listitem>

@@ -579,13 +751,26 @@ in config.someSetting</programlisting>
  </varlistentry>


-  <!--
-  <varlistentry><term><function>relativise</function></term>
+  <varlistentry><term><function>builtins.readDir</function>
+  <replaceable>path</replaceable></term>

-    <listitem><para>TODO</para></listitem>
+    <listitem><para>Return the contents of the directory
+    <replaceable>path</replaceable> as a set mapping directory entries
+    to the corresponding file type. For instance, if directory
+    <filename>A</filename> contains a regular file
+    <filename>B</filename> and another directory
+    <filename>C</filename>, then <literal>builtins.readDir
+    ./A</literal> will return the set
+
+<programlisting>
+{ B = "regular"; C = "directory"; }</programlisting>
+
+    The possible values for the file type are
+    <literal>"regular"</literal>, <literal>"directory"</literal>,
+    <literal>"symlink"</literal> and
+    <literal>"unknown"</literal>.</para></listitem>

  </varlistentry>
-  -->


  <varlistentry><term><function>builtins.readFile</function>
@@ -605,14 +790,65 @@ in config.someSetting</programlisting>
    <replaceable>set</replaceable>.  The attributes don’t have to
    exist in <replaceable>set</replaceable>. For instance,

-<screen>
-removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</screen>
+<programlisting>
+removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</programlisting>

    evaluates to <literal>{ y = 2; }</literal>.</para></listitem>

  </varlistentry>


+  <varlistentry><term><function>builtins.replaceStrings</function>
+  <replaceable>from</replaceable> <replaceable>to</replaceable> <replaceable>s</replaceable></term>
+
+    <listitem><para>Given string <replaceable>s</replaceable>, replace
+    every occurrence of the strings in <replaceable>from</replaceable>
+    with the corresponding string in
+    <replaceable>to</replaceable>. For example,
+
+<programlisting>
+builtins.replaceStrings ["oo" "a"] ["a" "i"] "foobar"
+</programlisting>
+
+    evaluates to <literal>"fabir"</literal>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.seq</function>
+  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
+
+    <listitem><para>Evaluate <replaceable>e1</replaceable>, then
+    evaluate and return <replaceable>e2</replaceable>. This ensures
+    that a computation is strict in the value of
+    <replaceable>e1</replaceable>.</para></listitem>
+
+  </varlistentry>
+
+
+  <varlistentry><term><function>builtins.sort</function>
+  <replaceable>comparator</replaceable> <replaceable>list</replaceable></term>
+
+    <listitem><para>Return <replaceable>list</replaceable> in sorted
+    order. It repeatedly calls the function
+    <replaceable>comparator</replaceable> with two elements. The
+    comparator should return <literal>true</literal> if the first
+    element is less than the second, and <literal>false</literal>
+    otherwise. For example,
+
+<programlisting>
+builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]
+</programlisting>
+
+    produces the list <literal>[ 42 77 147 249 483 526
+    ]</literal>.</para>
+
+    <para>This is a stable sort: it preserves the relative order of
+    elements deemed equal by the comparator.</para></listitem>
+
+  </varlistentry>
+
+
  <varlistentry><term><function>builtins.stringLength</function>
  <replaceable>e</replaceable></term>

@@ -626,7 +862,7 @@ removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</screen>
  <varlistentry><term><function>builtins.sub</function>
  <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>

-    <listitem><para>Return the difference between the integers
+    <listitem><para>Return the difference between the numbers
    <replaceable>e1</replaceable> and
    <replaceable>e2</replaceable>.</para></listitem>

@@ -646,7 +882,14 @@ removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]</screen>
    len</replaceable> lies beyond the end of the string, only the
    substring up to the end of the string is returned.
    <replaceable>start</replaceable> must be
-    non-negative.</para></listitem>
+    non-negative. For example,
+
+<programlisting>
+builtins.substring 0 3 "nixos"
+</programlisting>
+
+   evaluates to <literal>"nix"</literal>.
+   </para></listitem>

  </varlistentry>

@@ -753,7 +996,7 @@ in foo</programlisting>
  <varlistentry><term><function>builtins.toJSON</function> <replaceable>e</replaceable></term>

    <listitem><para>Return a string containing a JSON representation
-    of <replaceable>e</replaceable>.  Strings, integers, booleans,
+    of <replaceable>e</replaceable>.  Strings, integers, floats, booleans,
    nulls and lists are mapped to their JSON equivalents.  Sets
    (except derivations) are represented as objects.  Derivations are
    translated to a JSON string containing the derivation’s output
@@ -762,6 +1005,7 @@ in foo</programlisting>

  </varlistentry>

+
  <varlistentry><term><function>builtins.toPath</function> <replaceable>s</replaceable></term>

    <listitem><para>Convert the string value
@@ -780,9 +1024,9 @@ in foo</programlisting>
    <listitem><para>Convert the expression
    <replaceable>e</replaceable> to a string.
    <replaceable>e</replaceable> can be a string (in which case
-    <function>toString</function> is a no-op) or a path (e.g.,
+    <function>toString</function> is a no-op), a path (e.g.,
    <literal>toString /foo/bar</literal> yields
-    <literal>"/foo/bar"</literal>.</para></listitem>
+    <literal>"/foo/bar"</literal> or a set containing <literal>{ __toString = self: ...; }</literal>.</para></listitem>

  </varlistentry>

@@ -0,0 +1,34 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-debug-build">
+
+<title>Debugging Build Failures</title>
+
+<para>At the beginning of each phase of the build (such as unpacking,
+building or installing), the set of all shell variables is written to
+the file <filename>env-vars</filename> at the top-level build
+directory.  This is useful for debugging: it allows you to recreate
+the environment in which a build was performed.  For instance, if a
+build fails, then assuming you used the <option>-K</option> flag, you
+can go to the output directory and <quote>switch</quote> to the
+environment of the builder:
+
+<screen>
+$ nix-build -K ./foo.nix
+... fails, keeping build directory `/tmp/nix-1234-0'
+
+$ cd /tmp/nix-1234-0
+
+$ source env-vars
+
+<lineannotation>(edit some files...)</lineannotation>
+
+$ make
+
+<lineannotation>(execution continues with the same GCC, make, etc.)</lineannotation></screen>
+
+</para>
+
+</section>
@@ -0,0 +1,211 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-derivation">
+
+<title>Derivations</title>
+
+<para>The most important built-in function is
+<function>derivation</function>, which is used to describe a single
+derivation (a build action).  It takes as input a set, the attributes
+of which specify the inputs of the build.</para>
+
+<itemizedlist>
+
+  <listitem xml:id="attr-system"><para>There must be an attribute named
+  <varname>system</varname> whose value must be a string specifying a
+  Nix platform identifier, such as <literal>"i686-linux"</literal> or
+  <literal>"x86_64-darwin"</literal><footnote><para>To figure out
+  your platform identifier, look at the line <quote>Checking for the
+  canonical Nix system name</quote> in the output of Nix's
+  <filename>configure</filename> script.</para></footnote> The build
+  can only be performed on a machine and operating system matching the
+  platform identifier.  (Nix can automatically forward builds for
+  other platforms by forwarding them to other machines; see <xref
+  linkend='chap-distributed-builds' />.)</para></listitem>
+
+  <listitem><para>There must be an attribute named
+  <varname>name</varname> whose value must be a string.  This is used
+  as a symbolic name for the package by <command>nix-env</command>,
+  and it is appended to the output paths of the
+  derivation.</para></listitem>
+
+  <listitem><para>There must be an attribute named
+  <varname>builder</varname> that identifies the program that is
+  executed to perform the build.  It can be either a derivation or a
+  source (a local file reference, e.g.,
+  <filename>./builder.sh</filename>).</para></listitem>
+
+  <listitem><para>Every attribute is passed as an environment variable
+  to the builder.  Attribute values are translated to environment
+  variables as follows:
+
+    <itemizedlist>
+
+      <listitem><para>Strings and numbers are just passed
+      verbatim.</para></listitem>
+
+      <listitem><para>A <emphasis>path</emphasis> (e.g.,
+      <filename>../foo/sources.tar</filename>) causes the referenced
+      file to be copied to the store; its location in the store is put
+      in the environment variable.  The idea is that all sources
+      should reside in the Nix store, since all inputs to a derivation
+      should reside in the Nix store.</para></listitem>
+
+      <listitem><para>A <emphasis>derivation</emphasis> causes that
+      derivation to be built prior to the present derivation; its
+      default output path is put in the environment
+      variable.</para></listitem>
+
+      <listitem><para>Lists of the previous types are also allowed.
+      They are simply concatenated, separated by
+      spaces.</para></listitem>
+
+      <listitem><para><literal>true</literal> is passed as the string
+      <literal>1</literal>, <literal>false</literal> and
+      <literal>null</literal> are passed as an empty string.
+      </para></listitem>
+    </itemizedlist>
+
+  </para></listitem>
+
+  <listitem><para>The optional attribute <varname>args</varname>
+  specifies command-line arguments to be passed to the builder.  It
+  should be a list.</para></listitem>
+
+  <listitem><para>The optional attribute <varname>outputs</varname>
+  specifies a list of symbolic outputs of the derivation.  By default,
+  a derivation produces a single output path, denoted as
+  <literal>out</literal>.  However, derivations can produce multiple
+  output paths.  This is useful because it allows outputs to be
+  downloaded or garbage-collected separately.  For instance, imagine a
+  library package that provides a dynamic library, header files, and
+  documentation.  A program that links against the library doesn’t
+  need the header files and documentation at runtime, and it doesn’t
+  need the documentation at build time.  Thus, the library package
+  could specify:
+<programlisting>
+outputs = [ "lib" "headers" "doc" ];
+</programlisting>
+  This will cause Nix to pass environment variables
+  <literal>lib</literal>, <literal>headers</literal> and
+  <literal>doc</literal> to the builder containing the intended store
+  paths of each output.  The builder would typically do something like
+<programlisting>
+./configure --libdir=$lib/lib --includedir=$headers/include --docdir=$doc/share/doc
+</programlisting>
+  for an Autoconf-style package.  You can refer to each output of a
+  derivation by selecting it as an attribute, e.g.
+<programlisting>
+buildInputs = [ pkg.lib pkg.headers ];
+</programlisting>
+  The first element of <varname>output</varname> determines the
+  <emphasis>default output</emphasis>.  Thus, you could also write
+<programlisting>
+buildInputs = [ pkg pkg.headers ];
+</programlisting>
+  since <literal>pkg</literal> is equivalent to
+  <literal>pkg.lib</literal>.</para></listitem>
+
+</itemizedlist>
+
+<para>The function <function>mkDerivation</function> in the Nixpkgs
+standard environment is a wrapper around
+<function>derivation</function> that adds a default value for
+<varname>system</varname> and always uses Bash as the builder, to
+which the supplied builder is passed as a command-line argument.  See
+the Nixpkgs manual for details.</para>
+
+<para>The builder is executed as follows:
+
+<itemizedlist>
+
+  <listitem><para>A temporary directory is created under the directory
+  specified by <envar>TMPDIR</envar> (default
+  <filename>/tmp</filename>) where the build will take place.  The
+  current directory is changed to this directory.</para></listitem>
+
+  <listitem><para>The environment is cleared and set to the derivation
+  attributes, as specified above.</para></listitem>
+
+  <listitem><para>In addition, the following variables are set:
+
+  <itemizedlist>
+
+    <listitem><para><envar>NIX_BUILD_TOP</envar> contains the path of
+    the temporary directory for this build.</para></listitem>
+
+    <listitem><para>Also, <envar>TMPDIR</envar>,
+    <envar>TEMPDIR</envar>, <envar>TMP</envar>, <envar>TEMP</envar>
+    are set to point to the temporary directory.  This is to prevent
+    the builder from accidentally writing temporary files anywhere
+    else.  Doing so might cause interference by other
+    processes.</para></listitem>
+
+    <listitem><para><envar>PATH</envar> is set to
+    <filename>/path-not-set</filename> to prevent shells from
+    initialising it to their built-in default value.</para></listitem>
+
+    <listitem><para><envar>HOME</envar> is set to
+    <filename>/homeless-shelter</filename> to prevent programs from
+    using <filename>/etc/passwd</filename> or the like to find the
+    user's home directory, which could cause impurity.  Usually, when
+    <envar>HOME</envar> is set, it is used as the location of the home
+    directory, even if it points to a non-existent
+    path.</para></listitem>
+
+    <listitem><para><envar>NIX_STORE</envar> is set to the path of the
+    top-level Nix store directory (typically,
+    <filename>/nix/store</filename>).</para></listitem>
+
+    <listitem><para>For each output declared in
+    <varname>outputs</varname>, the corresponding environment variable
+    is set to point to the intended path in the Nix store for that
+    output.  Each output path is a concatenation of the cryptographic
+    hash of all build inputs, the <varname>name</varname> attribute
+    and the output name.  (The output name is omitted if it’s
+    <literal>out</literal>.)</para></listitem>
+
+  </itemizedlist>
+
+  </para></listitem>
+
+  <listitem><para>If an output path already exists, it is removed.
+  Also, locks are acquired to prevent multiple Nix instances from
+  performing the same build at the same time.</para></listitem>
+
+  <listitem><para>A log of the combined standard output and error is
+  written to <filename>/nix/var/log/nix</filename>.</para></listitem>
+
+  <listitem><para>The builder is executed with the arguments specified
+  by the attribute <varname>args</varname>.  If it exits with exit
+  code 0, it is considered to have succeeded.</para></listitem>
+
+  <listitem><para>The temporary directory is removed (unless the
+  <option>-K</option> option was specified).</para></listitem>
+
+  <listitem><para>If the build was successful, Nix scans each output
+  path for references to input paths by looking for the hash parts of
+  the input paths.  Since these are potential runtime dependencies,
+  Nix registers them as dependencies of the output
+  paths.</para></listitem>
+
+  <listitem><para>After the build, Nix sets the last-modified
+  timestamp on all files in the build result to 1 (00:00:01 1/1/1970
+  UTC), sets the group to the default group, and sets the mode of the
+  file to 0444 or 0555 (i.e., read-only, with execute permission
+  enabled if the file was originally executable).  Note that possible
+  <literal>setuid</literal> and <literal>setgid</literal> bits are
+  cleared.  Setuid and setgid programs are not currently supported by
+  Nix.  This is because the Nix archives used in deployment have no
+  concept of ownership information, and because it makes the build
+  result dependent on the user performing the build.</para></listitem>
+
+</itemizedlist>
+
+</para>
+
+<xi:include href="advanced-attributes.xml" />
+
+</section>
@@ -0,0 +1,30 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-expression-language">
+
+<title>Nix Expression Language</title>
+
+<para>The Nix expression language is a pure, lazy, functional
+language.  Purity means that operations in the language don't have
+side-effects (for instance, there is no variable assignment).
+Laziness means that arguments to functions are evaluated only when
+they are needed.  Functional means that functions are
+<quote>normal</quote> values that can be passed around and manipulated
+in interesting ways.  The language is not a full-featured, general
+purpose language.  Its main job is to describe packages,
+compositions of packages, and the variability within
+packages.</para>
+
+<para>This section presents the various features of the
+language.</para>
+
+<xi:include href="language-values.xml" />
+<xi:include href="language-constructs.xml" />
+<xi:include href="language-operators.xml" />
+<xi:include href="derivations.xml" />
+<xi:include href="builtins.xml" />
+
+
+</chapter>
@@ -0,0 +1,148 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-expression-syntax'>
+
+<title>Expression Syntax</title>
+
+<example xml:id='ex-hello-nix'><title>Nix expression for GNU Hello
+(<filename>default.nix</filename>)</title>
+<programlisting>
+{ stdenv, fetchurl, perl }: <co xml:id='ex-hello-nix-co-1' />
+
+stdenv.mkDerivation { <co xml:id='ex-hello-nix-co-2' />
+  name = "hello-2.1.1"; <co xml:id='ex-hello-nix-co-3' />
+  builder = ./builder.sh; <co xml:id='ex-hello-nix-co-4' />
+  src = fetchurl { <co xml:id='ex-hello-nix-co-5' />
+    url = ftp://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz;
+    md5 = "70c9ccf9fac07f762c24f2df2290784d";
+  };
+  inherit perl; <co xml:id='ex-hello-nix-co-6' />
+}</programlisting>
+</example>
+
+<para><xref linkend='ex-hello-nix' /> shows a Nix expression for GNU
+Hello.  It's actually already in the Nix Packages collection in
+<filename>pkgs/applications/misc/hello/ex-1/default.nix</filename>.
+It is customary to place each package in a separate directory and call
+the single Nix expression in that directory
+<filename>default.nix</filename>.  The file has the following elements
+(referenced from the figure by number):
+
+<calloutlist>
+
+  <callout arearefs='ex-hello-nix-co-1'>
+
+    <para>This states that the expression is a
+    <emphasis>function</emphasis> that expects to be called with three
+    arguments: <varname>stdenv</varname>, <varname>fetchurl</varname>,
+    and <varname>perl</varname>.  They are needed to build Hello, but
+    we don't know how to build them here; that's why they are function
+    arguments.  <varname>stdenv</varname> is a package that is used
+    by almost all Nix Packages packages; it provides a
+    <quote>standard</quote> environment consisting of the things you
+    would expect in a basic Unix environment: a C/C++ compiler (GCC,
+    to be precise), the Bash shell, fundamental Unix tools such as
+    <command>cp</command>, <command>grep</command>,
+    <command>tar</command>, etc.  <varname>fetchurl</varname> is a
+    function that downloads files.  <varname>perl</varname> is the
+    Perl interpreter.</para>
+
+    <para>Nix functions generally have the form <literal>{ x, y, ...,
+    z }: e</literal> where <varname>x</varname>, <varname>y</varname>,
+    etc. are the names of the expected arguments, and where
+    <replaceable>e</replaceable> is the body of the function.  So
+    here, the entire remainder of the file is the body of the
+    function; when given the required arguments, the body should
+    describe how to build an instance of the Hello package.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-nix-co-2'>
+
+    <para>So we have to build a package.  Building something from
+    other stuff is called a <emphasis>derivation</emphasis> in Nix (as
+    opposed to sources, which are built by humans instead of
+    computers).  We perform a derivation by calling
+    <varname>stdenv.mkDerivation</varname>.
+    <varname>mkDerivation</varname> is a function provided by
+    <varname>stdenv</varname> that builds a package from a set of
+    <emphasis>attributes</emphasis>.  A set is just a list of
+    key/value pairs where each key is a string and each value is an
+    arbitrary Nix expression.  They take the general form <literal>{
+    <replaceable>name1</replaceable> =
+    <replaceable>expr1</replaceable>; <replaceable>...</replaceable>
+    <replaceable>nameN</replaceable> =
+    <replaceable>exprN</replaceable>; }</literal>.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-nix-co-3'>
+
+    <para>The attribute <varname>name</varname> specifies the symbolic
+    name and version of the package.  Nix doesn't really care about
+    these things, but they are used by for instance <command>nix-env
+    -q</command> to show a <quote>human-readable</quote> name for
+    packages.  This attribute is required by
+    <varname>mkDerivation</varname>.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-nix-co-4'>
+
+    <para>The attribute <varname>builder</varname> specifies the
+    builder.  This attribute can sometimes be omitted, in which case
+    <varname>mkDerivation</varname> will fill in a default builder
+    (which does a <literal>configure; make; make install</literal>, in
+    essence).  Hello is sufficiently simple that the default builder
+    would suffice, but in this case, we will show an actual builder
+    for educational purposes.  The value
+    <command>./builder.sh</command> refers to the shell script shown
+    in <xref linkend='ex-hello-builder' />, discussed below.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-nix-co-5'>
+
+    <para>The builder has to know what the sources of the package
+    are.  Here, the attribute <varname>src</varname> is bound to the
+    result of a call to the <command>fetchurl</command> function.
+    Given a URL and an MD5 hash of the expected contents of the file
+    at that URL, this function builds a derivation that downloads the
+    file and checks its hash.  So the sources are a dependency that
+    like all other dependencies is built before Hello itself is
+    built.</para>
+
+    <para>Instead of <varname>src</varname> any other name could have
+    been used, and in fact there can be any number of sources (bound
+    to different attributes).  However, <varname>src</varname> is
+    customary, and it's also expected by the default builder (which we
+    don't use in this example).</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-nix-co-6'>
+
+    <para>Since the derivation requires Perl, we have to pass the
+    value of the <varname>perl</varname> function argument to the
+    builder.  All attributes in the set are actually passed as
+    environment variables to the builder, so declaring an attribute
+
+    <programlisting>
+perl = perl;</programlisting>
+
+    will do the trick: it binds an attribute <varname>perl</varname>
+    to the function argument which also happens to be called
+    <varname>perl</varname>.  However, it looks a bit silly, so there
+    is a shorter syntax.  The <literal>inherit</literal> keyword
+    causes the specified attributes to be bound to whatever variables
+    with the same name happen to be in scope.</para>
+
+  </callout>
+
+</calloutlist>
+
+</para>
+
+</section>
@@ -0,0 +1,98 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-generic-builder'>
+
+<title>Generic Builder Syntax</title>
+
+<para>Recall from <xref linkend='ex-hello-builder' /> that the builder
+looked something like this:
+
+<programlisting>
+PATH=$perl/bin:$PATH
+tar xvfz $src
+cd hello-*
+./configure --prefix=$out
+make
+make install</programlisting>
+
+The builders for almost all Unix packages look like this — set up some
+environment variables, unpack the sources, configure, build, and
+install.  For this reason the standard environment provides some Bash
+functions that automate the build process.  A builder using the
+generic build facilities in shown in <xref linkend='ex-hello-builder2'
+/>.</para>
+
+<example xml:id='ex-hello-builder2'><title>Build script using the generic
+build functions</title>
+<programlisting>
+buildInputs="$perl" <co xml:id='ex-hello-builder2-co-1' />
+
+source $stdenv/setup <co xml:id='ex-hello-builder2-co-2' />
+
+genericBuild <co xml:id='ex-hello-builder2-co-3' /></programlisting>
+</example>
+
+<calloutlist>
+
+  <callout arearefs='ex-hello-builder2-co-1'>
+
+    <para>The <envar>buildInputs</envar> variable tells
+    <filename>setup</filename> to use the indicated packages as
+    <quote>inputs</quote>.  This means that if a package provides a
+    <filename>bin</filename> subdirectory, it's added to
+    <envar>PATH</envar>; if it has a <filename>include</filename>
+    subdirectory, it's added to GCC's header search path; and so
+    on.<footnote><para>How does it work? <filename>setup</filename>
+    tries to source the file
+    <filename><replaceable>pkg</replaceable>/nix-support/setup-hook</filename>
+    of all dependencies.  These “setup hooks” can then set up whatever
+    environment variables they want; for instance, the setup hook for
+    Perl sets the <envar>PERL5LIB</envar> environment variable to
+    contain the <filename>lib/site_perl</filename> directories of all
+    inputs.</para></footnote>
+    </para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder2-co-2'>
+
+    <para>The function <function>genericBuild</function> is defined in
+    the file <literal>$stdenv/setup</literal>.</para>
+
+  </callout>
+
+  <callout arearefs='ex-hello-builder2-co-3'>
+
+    <para>The final step calls the shell function
+    <function>genericBuild</function>, which performs the steps that
+    were done explicitly in <xref linkend='ex-hello-builder' />.  The
+    generic builder is smart enough to figure out whether to unpack
+    the sources using <command>gzip</command>,
+    <command>bzip2</command>, etc.  It can be customised in many ways;
+    see the Nixpkgs manual for details.</para>
+
+  </callout>
+
+</calloutlist>
+
+<para>Discerning readers will note that the
+<envar>buildInputs</envar> could just as well have been set in the Nix
+expression, like this:
+
+<programlisting>
+  buildInputs = [ perl ];</programlisting>
+
+The <varname>perl</varname> attribute can then be removed, and the
+builder becomes even shorter:
+
+<programlisting>
+source $stdenv/setup
+genericBuild</programlisting>
+
+In fact, <varname>mkDerivation</varname> provides a default builder
+that looks exactly like that, so it is actually possible to omit the
+builder for Hello entirely.</para>
+
+</section>
@@ -0,0 +1,350 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-constructs">
+
+<title>Language Constructs</title>
+
+<simplesect><title>Recursive sets</title>
+
+<para>Recursive sets are just normal sets, but the attributes can
+refer to each other.  For example,
+
+<programlisting>
+rec {
+  x = y;
+  y = 123;
+}.x
+</programlisting>
+
+evaluates to <literal>123</literal>.  Note that without
+<literal>rec</literal> the binding <literal>x = y;</literal> would
+refer to the variable <varname>y</varname> in the surrounding scope,
+if one exists, and would be invalid if no such variable exists.  That
+is, in a normal (non-recursive) set, attributes are not added to the
+lexical scope; in a recursive set, they are.</para>
+
+<para>Recursive sets of course introduce the danger of infinite
+recursion.  For example,
+
+<programlisting>
+rec {
+  x = y;
+  y = x;
+}.x</programlisting>
+
+does not terminate<footnote><para>Actually, Nix detects infinite
+recursion in this case and aborts (<quote>infinite recursion
+encountered</quote>).</para></footnote>.</para>
+
+</simplesect>
+
+
+<simplesect><title>Let-expressions</title>
+
+<para>A let-expression allows you define local variables for an
+expression.  For instance,
+
+<programlisting>
+let
+  x = "foo";
+  y = "bar";
+in x + y</programlisting>
+
+evaluates to <literal>"foobar"</literal>.
+
+</para>
+
+</simplesect>
+
+
+<simplesect><title>Inheriting attributes</title>
+
+<para>When defining a set it is often convenient to copy variables
+from the surrounding lexical scope (e.g., when you want to propagate
+attributes).  This can be shortened using the
+<literal>inherit</literal> keyword.  For instance,
+
+<programlisting>
+let x = 123; in
+{ inherit x;
+  y = 456;
+}</programlisting>
+
+evaluates to <literal>{ x = 123; y = 456; }</literal>.  (Note that
+this works because <varname>x</varname> is added to the lexical scope
+by the <literal>let</literal> construct.)  It is also possible to
+inherit attributes from another set.  For instance, in this fragment
+from <filename>all-packages.nix</filename>,
+
+<programlisting>
+  graphviz = (import ../tools/graphics/graphviz) {
+    inherit fetchurl stdenv libpng libjpeg expat x11 yacc;
+    inherit (xlibs) libXaw;
+  };
+
+  xlibs = {
+    libX11 = ...;
+    libXaw = ...;
+    ...
+  }
+
+  libpng = ...;
+  libjpg = ...;
+  ...</programlisting>
+
+the set used in the function call to the function defined in
+<filename>../tools/graphics/graphviz</filename> inherits a number of
+variables from the surrounding scope (<varname>fetchurl</varname>
+... <varname>yacc</varname>), but also inherits
+<varname>libXaw</varname> (the X Athena Widgets) from the
+<varname>xlibs</varname> (X11 client-side libraries) set.</para>
+
+</simplesect>
+
+
+<simplesect xml:id="ss-functions"><title>Functions</title>
+
+<para>Functions have the following form:
+
+<programlisting>
+<replaceable>pattern</replaceable>: <replaceable>body</replaceable></programlisting>
+
+The pattern specifies what the argument of the function must look
+like, and binds variables in the body to (parts of) the
+argument.  There are three kinds of patterns:</para>
+
+<itemizedlist>
+
+
+  <listitem><para>If a pattern is a single identifier, then the
+  function matches any argument.  Example:
+
+  <programlisting>
+let negate = x: !x;
+    concat = x: y: x + y;
+in if negate true then concat "foo" "bar" else ""</programlisting>
+
+  Note that <function>concat</function> is a function that takes one
+  argument and returns a function that takes another argument.  This
+  allows partial parameterisation (i.e., only filling some of the
+  arguments of a function); e.g.,
+
+  <programlisting>
+map (concat "foo") [ "bar" "bla" "abc" ]</programlisting>
+
+  evaluates to <literal>[ "foobar" "foobla"
+  "fooabc" ]</literal>.</para></listitem>
+
+
+  <listitem><para>A <emphasis>set pattern</emphasis> of the form
+  <literal>{ name1, name2, …, nameN }</literal> matches a set
+  containing the listed attributes, and binds the values of those
+  attributes to variables in the function body.  For example, the
+  function
+
+<programlisting>
+{ x, y, z }: z + y + x</programlisting>
+
+  can only be called with a set containing exactly the attributes
+  <varname>x</varname>, <varname>y</varname> and
+  <varname>z</varname>.  No other attributes are allowed.  If you want
+  to allow additional arguments, you can use an ellipsis
+  (<literal>...</literal>):
+
+<programlisting>
+{ x, y, z, ... }: z + y + x</programlisting>
+
+  This works on any set that contains at least the three named
+  attributes.</para>
+
+  <para>It is possible to provide <emphasis>default values</emphasis>
+  for attributes, in which case they are allowed to be missing.  A
+  default value is specified by writing
+  <literal><replaceable>name</replaceable> ?
+  <replaceable>e</replaceable></literal>, where
+  <replaceable>e</replaceable> is an arbitrary expression.  For example,
+
+<programlisting>
+{ x, y ? "foo", z ? "bar" }: z + y + x</programlisting>
+
+  specifies a function that only requires an attribute named
+  <varname>x</varname>, but optionally accepts <varname>y</varname>
+  and <varname>z</varname>.</para></listitem>
+
+
+  <listitem><para>An <literal>@</literal>-pattern provides a means of referring
+  to the whole value being matched:
+
+<programlisting> args@{ x, y, z, ... }: z + y + x + args.a</programlisting>
+
+but can also be written as:
+
+<programlisting> { x, y, z, ... } @ args: z + y + x + args.a</programlisting>
+
+  Here <varname>args</varname> is bound to the entire argument, which
+  is further matched against the pattern <literal>{ x, y, z,
+  ... }</literal>. <literal>@</literal>-pattern makes mainly sense with an 
+  ellipsis(<literal>...</literal>) as you can access attribute names as 
+  <literal>a</literal>, using <literal>args.a</literal>, which was given as an
+  additional attribute to the function.
+  </para></listitem>
+
+</itemizedlist>
+
+<para>Note that functions do not have names.  If you want to give them
+a name, you can bind them to an attribute, e.g.,
+
+<programlisting>
+let concat = { x, y }: x + y;
+in concat { x = "foo"; y = "bar"; }</programlisting>
+
+</para>
+
+</simplesect>
+
+
+<simplesect><title>Conditionals</title>
+
+<para>Conditionals look like this:
+
+<programlisting>
+if <replaceable>e1</replaceable> then <replaceable>e2</replaceable> else <replaceable>e3</replaceable></programlisting>
+
+where <replaceable>e1</replaceable> is an expression that should
+evaluate to a Boolean value (<literal>true</literal> or
+<literal>false</literal>).</para>
+
+</simplesect>
+
+
+<simplesect><title>Assertions</title>
+
+<para>Assertions are generally used to check that certain requirements
+on or between features and dependencies hold.  They look like this:
+
+<programlisting>
+assert <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting>
+
+where <replaceable>e1</replaceable> is an expression that should
+evaluate to a Boolean value.  If it evaluates to
+<literal>true</literal>, <replaceable>e2</replaceable> is returned;
+otherwise expression evaluation is aborted and a backtrace is printed.</para>
+
+<example xml:id='ex-subversion-nix'><title>Nix expression for Subversion</title>
+<programlisting>
+{ localServer ? false
+, httpServer ? false
+, sslSupport ? false
+, pythonBindings ? false
+, javaSwigBindings ? false
+, javahlBindings ? false
+, stdenv, fetchurl
+, openssl ? null, httpd ? null, db4 ? null, expat, swig ? null, j2sdk ? null
+}:
+
+assert localServer -> db4 != null; <co xml:id='ex-subversion-nix-co-1' />
+assert httpServer -> httpd != null &amp;&amp; httpd.expat == expat; <co xml:id='ex-subversion-nix-co-2' />
+assert sslSupport -> openssl != null &amp;&amp; (httpServer -> httpd.openssl == openssl); <co xml:id='ex-subversion-nix-co-3' />
+assert pythonBindings -> swig != null &amp;&amp; swig.pythonSupport;
+assert javaSwigBindings -> swig != null &amp;&amp; swig.javaSupport;
+assert javahlBindings -> j2sdk != null;
+
+stdenv.mkDerivation {
+  name = "subversion-1.1.1";
+  ...
+  openssl = if sslSupport then openssl else null; <co xml:id='ex-subversion-nix-co-4' />
+  ...
+}</programlisting>
+</example>
+
+<para><xref linkend='ex-subversion-nix' /> show how assertions are
+used in the Nix expression for Subversion.</para>
+
+<calloutlist>
+
+  <callout arearefs='ex-subversion-nix-co-1'>
+    <para>This assertion states that if Subversion is to have support
+    for local repositories, then Berkeley DB is needed.  So if the
+    Subversion function is called with the
+    <varname>localServer</varname> argument set to
+    <literal>true</literal> but the <varname>db4</varname> argument
+    set to <literal>null</literal>, then the evaluation fails.</para>
+  </callout>
+
+  <callout arearefs='ex-subversion-nix-co-2'>
+    <para>This is a more subtle condition: if Subversion is built with
+    Apache (<literal>httpServer</literal>) support, then the Expat
+    library (an XML library) used by Subversion should be same as the
+    one used by Apache.  This is because in this configuration
+    Subversion code ends up being linked with Apache code, and if the
+    Expat libraries do not match, a build- or runtime link error or
+    incompatibility might occur.</para>
+  </callout>
+
+  <callout arearefs='ex-subversion-nix-co-3'>
+    <para>This assertion says that in order for Subversion to have SSL
+    support (so that it can access <literal>https</literal> URLs), an
+    OpenSSL library must be passed.  Additionally, it says that
+    <emphasis>if</emphasis> Apache support is enabled, then Apache's
+    OpenSSL should match Subversion's.  (Note that if Apache support
+    is not enabled, we don't care about Apache's OpenSSL.)</para>
+  </callout>
+
+  <callout arearefs='ex-subversion-nix-co-4'>
+    <para>The conditional here is not really related to assertions,
+    but is worth pointing out: it ensures that if SSL support is
+    disabled, then the Subversion derivation is not dependent on
+    OpenSSL, even if a non-<literal>null</literal> value was passed.
+    This prevents an unnecessary rebuild of Subversion if OpenSSL
+    changes.</para>
+  </callout>
+
+</calloutlist>
+
+</simplesect>
+
+
+
+<simplesect><title>With-expressions</title>
+
+<para>A <emphasis>with-expression</emphasis>,
+
+<programlisting>
+with <replaceable>e1</replaceable>; <replaceable>e2</replaceable></programlisting>
+
+introduces the set <replaceable>e1</replaceable> into the lexical
+scope of the expression <replaceable>e2</replaceable>.  For instance,
+
+<programlisting>
+let as = { x = "foo"; y = "bar"; };
+in with as; x + y</programlisting>
+
+evaluates to <literal>"foobar"</literal> since the
+<literal>with</literal> adds the <varname>x</varname> and
+<varname>y</varname> attributes of <varname>as</varname> to the
+lexical scope in the expression <literal>x + y</literal>.  The most
+common use of <literal>with</literal> is in conjunction with the
+<function>import</function> function.  E.g.,
+
+<programlisting>
+with (import ./definitions.nix); ...</programlisting>
+
+makes all attributes defined in the file
+<filename>definitions.nix</filename> available as if they were defined
+locally in a <literal>rec</literal>-expression.</para>
+
+</simplesect>
+
+
+<simplesect><title>Comments</title>
+
+<para>Comments can be single-line, started with a <literal>#</literal>
+character, or inline/multi-line, enclosed within <literal>/*
+... */</literal>.</para>
+
+</simplesect>
+
+
+</section>
@@ -0,0 +1,113 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-language-operators">
+
+<title>Operators</title>
+
+<para><xref linkend='table-operators' /> lists the operators in the
+Nix expression language, in order of precedence (from strongest to
+weakest binding).</para>
+
+<table xml:id='table-operators'>
+  <title>Operators</title>
+  <tgroup cols='3'>
+    <thead>
+      <row>
+        <entry>Syntax</entry>
+        <entry>Associativity</entry>
+        <entry>Description</entry>
+      </row>
+    </thead>
+    <tbody>
+      <row>
+        <entry><replaceable>e</replaceable> <literal>.</literal>
+        <replaceable>attrpath</replaceable>
+        [ <literal>or</literal> <replaceable>def</replaceable> ]
+        </entry>
+        <entry>none</entry>
+        <entry>Select attribute denoted by the attribute path
+        <replaceable>attrpath</replaceable> from set
+        <replaceable>e</replaceable>.  (An attribute path is a
+        dot-separated list of attribute names.)  If the attribute
+        doesn’t exist, return <replaceable>def</replaceable> if
+        provided, otherwise abort evaluation.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <replaceable>e2</replaceable></entry>
+        <entry>left</entry>
+        <entry>Call function <replaceable>e1</replaceable> with
+        argument <replaceable>e2</replaceable>.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e</replaceable> <literal>?</literal>
+        <replaceable>attrpath</replaceable></entry>
+        <entry>none</entry>
+        <entry>Test whether set <replaceable>e</replaceable> contains
+        the attribute denoted by <replaceable>attrpath</replaceable>;
+        return <literal>true</literal> or
+        <literal>false</literal>.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>++</literal> <replaceable>e2</replaceable></entry>
+        <entry>right</entry>
+        <entry>List concatenation.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable></entry>
+        <entry>left</entry>
+        <entry>String or path concatenation.</entry>
+      </row>
+      <row>
+        <entry><literal>!</literal> <replaceable>e</replaceable></entry>
+        <entry>left</entry>
+        <entry>Boolean negation.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>//</literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>right</entry>
+        <entry>Return a set consisting of the attributes in
+        <replaceable>e1</replaceable> and
+        <replaceable>e2</replaceable> (with the latter taking
+        precedence over the former in case of equally named
+        attributes).</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>==</literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>none</entry>
+        <entry>Equality.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>!=</literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>none</entry>
+        <entry>Inequality.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>&amp;&amp;</literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>left</entry>
+        <entry>Logical AND.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>||</literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>left</entry>
+        <entry>Logical OR.</entry>
+      </row>
+      <row>
+        <entry><replaceable>e1</replaceable> <literal>-></literal>
+        <replaceable>e2</replaceable></entry>
+        <entry>none</entry>
+        <entry>Logical implication (equivalent to
+        <literal>!<replaceable>e1</replaceable> ||
+        <replaceable>e2</replaceable></literal>).</entry>
+      </row>
+    </tbody>
+  </tgroup>
+</table>
+
+</section>
@@ -0,0 +1,309 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='ssec-values'>
+
+<title>Values</title>
+
+
+<simplesect><title>Simple Values</title>
+
+<para>Nix has the following basic data types:
+
+<itemizedlist>
+
+  <listitem>
+
+    <para><emphasis>Strings</emphasis> can be written in three
+    ways.</para>
+
+    <para>The most common way is to enclose the string between double
+    quotes, e.g., <literal>"foo bar"</literal>.  Strings can span
+    multiple lines.  The special characters <literal>"</literal> and
+    <literal>\</literal> and the character sequence
+    <literal>${</literal> must be escaped by prefixing them with a
+    backslash (<literal>\</literal>).  Newlines, carriage returns and
+    tabs can be written as <literal>\n</literal>,
+    <literal>\r</literal> and <literal>\t</literal>,
+    respectively.</para>
+
+    <para>You can include the result of an expression into a string by
+    enclosing it in
+    <literal>${<replaceable>...</replaceable>}</literal>, a feature
+    known as <emphasis>antiquotation</emphasis>.  The enclosed
+    expression must evaluate to something that can be coerced into a
+    string (meaning that it must be a string, a path, or a
+    derivation).  For instance, rather than writing
+
+<programlisting>
+"--with-freetype2-library=" + freetype + "/lib"</programlisting>
+
+    (where <varname>freetype</varname> is a derivation), you can
+    instead write the more natural
+
+<programlisting>
+"--with-freetype2-library=${freetype}/lib"</programlisting>
+
+    The latter is automatically translated to the former.  A more
+    complicated example (from the Nix expression for <link
+    xlink:href='http://www.trolltech.com/products/qt'>Qt</link>):
+
+<programlisting>
+configureFlags = "
+  -system-zlib -system-libpng -system-libjpeg
+  ${if openglSupport then "-dlopen-opengl
+    -L${mesa}/lib -I${mesa}/include
+    -L${libXmu}/lib -I${libXmu}/include" else ""}
+  ${if threadSupport then "-thread" else "-no-thread"}
+";</programlisting>
+
+    Note that Nix expressions and strings can be arbitrarily nested;
+    in this case the outer string contains various antiquotations that
+    themselves contain strings (e.g., <literal>"-thread"</literal>),
+    some of which in turn contain expressions (e.g.,
+    <literal>${mesa}</literal>).</para>
+
+    <para>The second way to write string literals is as an
+    <emphasis>indented string</emphasis>, which is enclosed between
+    pairs of <emphasis>double single-quotes</emphasis>, like so:
+
+<programlisting>
+''
+  This is the first line.
+  This is the second line.
+    This is the third line.
+''</programlisting>
+
+    This kind of string literal intelligently strips indentation from
+    the start of each line.  To be precise, it strips from each line a
+    number of spaces equal to the minimal indentation of the string as
+    a whole (disregarding the indentation of empty lines).  For
+    instance, the first and second line are indented two space, while
+    the third line is indented four spaces.  Thus, two spaces are
+    stripped from each line, so the resulting string is
+
+<programlisting>
+"This is the first line.\nThis is the second line.\n  This is the third line.\n"</programlisting>
+
+    </para>
+
+    <para>Note that the whitespace and newline following the opening
+    <literal>''</literal> is ignored if there is no non-whitespace
+    text on the initial line.</para>
+
+    <para>Antiquotation
+    (<literal>${<replaceable>expr</replaceable>}</literal>) is
+    supported in indented strings.</para>
+
+    <para>Since <literal>${</literal> and <literal>''</literal> have
+    special meaning in indented strings, you need a way to quote them.
+    <literal>${</literal> can be escaped by prefixing it with
+    <literal>''</literal> (that is, two single quotes), i.e.,
+    <literal>''${</literal>.  <literal>''</literal> can be escaped by
+    prefixing it with <literal>'</literal>, i.e.,
+    <literal>'''</literal>.  Finally, linefeed, carriage-return and
+    tab characters can be written as <literal>''\n</literal>,
+    <literal>''\r</literal>, <literal>''\t</literal>.</para>
+
+    <para>Indented strings are primarily useful in that they allow
+    multi-line string literals to follow the indentation of the
+    enclosing Nix expression, and that less escaping is typically
+    necessary for strings representing languages such as shell scripts
+    and configuration files because <literal>''</literal> is much less
+    common than <literal>"</literal>.  Example:
+
+<programlisting>
+stdenv.mkDerivation {
+  <replaceable>...</replaceable>
+  postInstall =
+    ''
+      mkdir $out/bin $out/etc
+      cp foo $out/bin
+      echo "Hello World" > $out/etc/foo.conf
+      ${if enableBar then "cp bar $out/bin" else ""}
+    '';
+  <replaceable>...</replaceable>
+}
+</programlisting>
+
+    </para>
+
+    <para>Finally, as a convenience, <emphasis>URIs</emphasis> as
+    defined in appendix B of <link
+    xlink:href='http://www.ietf.org/rfc/rfc2396.txt'>RFC 2396</link>
+    can be written <emphasis>as is</emphasis>, without quotes.  For
+    instance, the string
+    <literal>"http://example.org/foo.tar.bz2"</literal>
+    can also be written as
+    <literal>http://example.org/foo.tar.bz2</literal>.</para>
+
+  </listitem>
+
+  <listitem><para>Numbers, which can be <emphasis>integers</emphasis> (like
+  <literal>123</literal>) or <emphasis>floating point</emphasis> (like
+  <literal>123.43</literal> or <literal>.27e13</literal>).</para>
+
+  <para>Numbers are type-compatible: pure integer operations will always
+  return integers, whereas any operation involving at least one floating point
+  number will have a floating point number as a result.</para></listitem>
+
+  <listitem><para><emphasis>Paths</emphasis>, e.g.,
+  <filename>/bin/sh</filename> or <filename>./builder.sh</filename>.
+  A path must contain at least one slash to be recognised as such; for
+  instance, <filename>builder.sh</filename> is not a
+  path<footnote><para>It's parsed as an expression that selects the
+  attribute <varname>sh</varname> from the variable
+  <varname>builder</varname>.</para></footnote>.  If the file name is
+  relative, i.e., if it does not begin with a slash, it is made
+  absolute at parse time relative to the directory of the Nix
+  expression that contained it.  For instance, if a Nix expression in
+  <filename>/foo/bar/bla.nix</filename> refers to
+  <filename>../xyzzy/fnord.nix</filename>, the absolute path is
+  <filename>/foo/xyzzy/fnord.nix</filename>.</para>
+
+  <para>If the first component of a path is a <literal>~</literal>,
+  it is interpreted as if the rest of the path were relative to the
+  user's home directory. e.g. <filename>~/foo</filename> would be
+  equivalent to <filename>/home/edolstra/foo</filename> for a user
+  whose home directory is <filename>/home/edolstra</filename>.
+  </para>
+
+  <para>Paths can also be specified between angle brackets, e.g.
+  <literal>&lt;nixpkgs&gt;</literal>. This means that the directories
+  listed in the environment variable
+  <envar linkend="env-NIX_PATH">NIX_PATH</envar> will be searched
+  for the given file or directory name.
+  </para>
+
+  </listitem>
+
+  <listitem><para><emphasis>Booleans</emphasis> with values
+  <literal>true</literal> and
+  <literal>false</literal>.</para></listitem>
+
+  <listitem><para>The null value, denoted as
+  <literal>null</literal>.</para></listitem>
+
+</itemizedlist>
+
+</para>
+
+</simplesect>
+
+
+<simplesect><title>Lists</title>
+
+<para>Lists are formed by enclosing a whitespace-separated list of
+values between square brackets.  For example,
+
+<programlisting>
+[ 123 ./foo.nix "abc" (f { x = y; }) ]</programlisting>
+
+defines a list of four elements, the last being the result of a call
+to the function <varname>f</varname>.  Note that function calls have
+to be enclosed in parentheses.  If they had been omitted, e.g.,
+
+<programlisting>
+[ 123 ./foo.nix "abc" f { x = y; } ]</programlisting>
+
+the result would be a list of five elements, the fourth one being a
+function and the fifth being a set.</para>
+
+<para>Note that lists are only lazy in values, and they are strict in length.
+</para>
+
+</simplesect>
+
+
+<simplesect><title>Sets</title>
+
+<para>Sets are really the core of the language, since ultimately the
+Nix language is all about creating derivations, which are really just
+sets of attributes to be passed to build scripts.</para>
+
+<para>Sets are just a list of name/value pairs (called
+<emphasis>attributes</emphasis>) enclosed in curly brackets, where
+each value is an arbitrary expression terminated by a semicolon.  For
+example:
+
+<programlisting>
+{ x = 123;
+  text = "Hello";
+  y = f { bla = 456; };
+}</programlisting>
+
+This defines a set with attributes named <varname>x</varname>,
+<varname>text</varname>, <varname>y</varname>.  The order of the
+attributes is irrelevant.  An attribute name may only occur
+once.</para>
+
+<para>Attributes can be selected from a set using the
+<literal>.</literal> operator.  For instance,
+
+<programlisting>
+{ a = "Foo"; b = "Bar"; }.a</programlisting>
+
+evaluates to <literal>"Foo"</literal>.  It is possible to provide a
+default value in an attribute selection using the
+<literal>or</literal> keyword.  For example,
+
+<programlisting>
+{ a = "Foo"; b = "Bar"; }.c or "Xyzzy"</programlisting>
+
+will evaluate to <literal>"Xyzzy"</literal> because there is no
+<varname>c</varname> attribute in the set.</para>
+
+<para>You can use arbitrary double-quoted strings as attribute
+names:
+
+<programlisting>
+{ "foo ${bar}" = 123; "nix-1.0" = 456; }."foo ${bar}"
+</programlisting>
+
+This will evaluate to <literal>123</literal> (Assuming
+<literal>bar</literal> is antiquotable). In the case where an
+attribute name is just a single antiquotation, the quotes can be
+dropped:
+
+<programlisting>
+{ foo = 123; }.${bar} or 456 </programlisting>
+
+This will evaluate to <literal>123</literal> if
+<literal>bar</literal> evaluates to <literal>"foo"</literal> when
+coerced to a string and <literal>456</literal> otherwise (again
+assuming <literal>bar</literal> is antiquotable).</para>
+
+<para>In the special case where an attribute name inside of a set declaration
+evaluates to <literal>null</literal> (which is normally an error, as
+<literal>null</literal> is not antiquotable), that attribute is simply not
+added to the set:
+
+<programlisting>
+{ ${if foo then "bar" else null} = true; }</programlisting>
+
+This will evaluate to <literal>{}</literal> if <literal>foo</literal>
+evaluates to <literal>false</literal>.</para>
+
+<para>A set that has a <literal>__functor</literal> attribute whose value
+is callable (i.e. is itself a function or a set with a
+<literal>__functor</literal> attribute whose value is callable) can be
+applied as if it were a function, with the set itself passed in first
+, e.g.,
+
+<programlisting>
+let add = { __functor = self: x: x + self.x; };
+    inc = add // { x = 1; };
+in inc 1
+</programlisting>
+
+evaluates to <literal>2</literal>. This can be used to attach metadata to a
+function without the caller needing to treat it specially, or to implement
+a form of object-oriented programming, for example.
+
+</para>
+
+</simplesect>
+
+
+</section>
@@ -0,0 +1,86 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-building-simple'>
+
+<title>Building and Testing</title>
+
+<para>You can now try to build Hello.  Of course, you could do
+<literal>nix-env -i hello</literal>, but you may not want to install a
+possibly broken package just yet.  The best way to test the package is by
+using the command <command linkend="sec-nix-build">nix-build</command>,
+which builds a Nix expression and creates a symlink named
+<filename>result</filename> in the current directory:
+
+<screen>
+$ nix-build -A hello
+building path `/nix/store/632d2b22514d...-hello-2.1.1'
+hello-2.1.1/
+hello-2.1.1/intl/
+hello-2.1.1/intl/ChangeLog
+<replaceable>...</replaceable>
+
+$ ls -l result
+lrwxrwxrwx ... 2006-09-29 10:43 result -> /nix/store/632d2b22514d...-hello-2.1.1
+
+$ ./result/bin/hello
+Hello, world!</screen>
+
+The <link linkend='opt-attr'><option>-A</option></link> option selects
+the <literal>hello</literal> attribute.  This is faster than using the
+symbolic package name specified by the <literal>name</literal>
+attribute (which also happens to be <literal>hello</literal>) and is
+unambiguous (there can be multiple packages with the symbolic name
+<literal>hello</literal>, but there can be only one attribute in a set
+named <literal>hello</literal>).</para>
+
+<para><command>nix-build</command> registers the
+<filename>./result</filename> symlink as a garbage collection root, so
+unless and until you delete the <filename>./result</filename> symlink,
+the output of the build will be safely kept on your system.  You can
+use <command>nix-build</command>’s <option
+linkend='opt-out-link'>-o</option> switch to give the symlink another
+name.</para>
+
+<para>Nix has a transactional semantics.  Once a build finishes
+successfully, Nix makes a note of this in its database: it registers
+that the path denoted by <envar>out</envar> is now
+<quote>valid</quote>.  If you try to build the derivation again, Nix
+will see that the path is already valid and finish immediately.  If a
+build fails, either because it returns a non-zero exit code, because
+Nix or the builder are killed, or because the machine crashes, then
+the output paths will not be registered as valid.  If you try to build
+the derivation again, Nix will remove the output paths if they exist
+(e.g., because the builder died half-way through <literal>make
+install</literal>) and try again.  Note that there is no
+<quote>negative caching</quote>: Nix doesn't remember that a build
+failed, and so a failed build can always be repeated.  This is because
+Nix cannot distinguish between permanent failures (e.g., a compiler
+error due to a syntax error in the source) and transient failures
+(e.g., a disk full condition).</para>
+
+<para>Nix also performs locking.  If you run multiple Nix builds
+simultaneously, and they try to build the same derivation, the first
+Nix instance that gets there will perform the build, while the others
+block (or perform other derivations if available) until the build
+finishes:
+
+<screen>
+$ nix-build -A hello
+waiting for lock on `/nix/store/0h5b7hp8d4hqfrw8igvx97x1xawrjnac-hello-2.1.1x'</screen>
+
+So it is always safe to run multiple instances of Nix in parallel
+(which isn’t the case with, say, <command>make</command>).</para>
+
+<para>If you have a system with multiple CPUs, you may want to have
+Nix build different derivations in parallel (insofar as possible).
+Just pass the option <link linkend='opt-max-jobs'><option>-j
+<replaceable>N</replaceable></option></link>, where
+<replaceable>N</replaceable> is the maximum number of jobs to be run
+in parallel, or set.  Typically this should be the number of
+CPUs.</para>
+
+<xi:include href="debug-build.xml" />
+
+</section>
@@ -0,0 +1,47 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-simple-expression">
+
+<title>A Simple Nix Expression</title>
+
+<para>This section shows how to add and test the <link
+xlink:href='http://www.gnu.org/software/hello/hello.html'>GNU Hello
+package</link> to the Nix Packages collection.  Hello is a program
+that prints out the text <quote>Hello, world!</quote>.</para>
+
+<para>To add a package to the Nix Packages collection, you generally
+need to do three things:
+
+<orderedlist>
+
+  <listitem><para>Write a Nix expression for the package.  This is a
+  file that describes all the inputs involved in building the package,
+  such as dependencies, sources, and so on.</para></listitem>
+
+  <listitem><para>Write a <emphasis>builder</emphasis>.  This is a
+  shell script<footnote><para>In fact, it can be written in any
+  language, but typically it's a <command>bash</command> shell
+  script.</para></footnote> that actually builds the package from
+  the inputs.</para></listitem>
+
+  <listitem><para>Add the package to the file
+  <filename>pkgs/top-level/all-packages.nix</filename>.  The Nix
+  expression written in the first step is a
+  <emphasis>function</emphasis>; it requires other packages in order
+  to build it.  In this step you put it all together, i.e., you call
+  the function with the right arguments to build the actual
+  package.</para></listitem>
+
+</orderedlist>
+
+</para>
+
+<xi:include href="expression-syntax.xml" />
+<xi:include href="build-script.xml" />
+<xi:include href="arguments-variables.xml" />
+<xi:include href="simple-building-testing.xml" />
+<xi:include href="generic-builder.xml" />
+
+</chapter>
@@ -0,0 +1,26 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='chap-writing-nix-expressions'>
+
+<title>Writing Nix Expressions</title>
+
+<partintro>
+<para>This chapter shows you how to write Nix expressions, which 
+instruct Nix how to build packages.  It starts with a
+simple example (a Nix expression for GNU Hello), and then moves
+on to a more in-depth look at the Nix expression language.</para>
+
+<note><para>This chapter is mostly about the Nix expression language.
+For more extensive information on adding packages to the Nix Packages
+collection (such as functions in the standard environment and coding
+conventions), please consult <link
+xlink:href="http://nixos.org/nixpkgs/manual/">its
+manual</link>.</para></note>
+</partintro>
+
+<xi:include href="simple-expression.xml" />
+<xi:include href="expression-language.xml" />
+
+</part>
@@ -22,15 +22,15 @@ $ nix-build release.nix -A build.x86_64-linux
 environment variables are set up so that those dependencies can be
 found:
 <screen>
-$ ./dev-shell
+$ nix-shell
 </screen>
 To build Nix itself in this shell:
 <screen>
-[nix-shell]$ ./bootstrap
+[nix-shell]$ ./bootstrap.sh
 [nix-shell]$ configurePhase
 [nix-shell]$ make
 </screen>
-To test it:
+To install it in <literal>$(pwd)/nix</literal> and test it:
 <screen>
 [nix-shell]$ make install
 [nix-shell]$ make installcheck
@@ -1,484 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id="chap-installation">
-
-<title>Installation</title>
-
-
-<section><title>Supported platforms</title>
-
-<para>Nix is currently supported on the following platforms:
-
-<itemizedlist>
-
-  <listitem><para>Linux (particularly on x86, x86_64, and
-  PowerPC).</para></listitem>
-
-  <listitem><para>Mac OS X.</para></listitem>
-
-  <listitem><para>FreeBSD (only tested on Intel).</para></listitem>
-
-  <!--
-  <listitem><para>Windows through <link
-  xlink:href="http://www.cygwin.com/">Cygwin</link>.</para>
-
-  <warning><para>On Cygwin, Nix <emphasis>must</emphasis> be installed
-  on an NTFS partition.  It will not work correctly on a FAT
-  partition.</para></warning>
-
-  </listitem>
-  -->
-
-</itemizedlist>
-
-</para>
-
-<para>Nix is pretty portable, so it should work on most other Unix
-platforms as well.</para>
-
-</section>
-
-
-<section><title>Installing a binary distribution</title>
-
-<para>The easiest way to install Nix is to run the following:
-
-<screen>
-$ bash &lt;(curl https://nixos.org/nix/install)
-</screen>
-
-This will perform a single-user installation of Nix, meaning that
-<filename>/nix</filename> is owned by the invoking user.  You should
-run this under your usual user account, <emphasis>not</emphasis> as
-root.  The script will invoke <command>sudo</command> to create
-<filename>/nix</filename> if it doesn’t already exist.  If you don’t
-have <command>sudo</command>, you should manually create
-<command>/nix</command> first as root:
-
-<screen>
-$ mkdir /nix
-$ chown alice /nix
-</screen>
-
-</para>
-
-<para>You can also manually download and install a binary package.
-Binary packages of the latest stable release are available for Fedora,
-Debian, Ubuntu, Mac OS X and various other systems from the <link
-xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
-You can also get builds of the latest development release from our
-<link
-xlink:href="http://hydra.nixos.org/job/nix/trunk/release/latest-finished#tabs-constituents">continuous
-build system</link>.</para>
-
-<para>For Fedora, RPM packages are available.  These can be installed
-or upgraded using <command>rpm -U</command>.  For example,
-
-<screen>
-$ rpm -U nix-1.7-1.i386.rpm</screen>
-
-</para>
-
-<para>For Debian and Ubuntu, you can download a Deb package and
-install it like this:
-
-<screen>
-$ dpkg -i nix_1.7-1_amd64.deb</screen>
-
-</para>
-
-<para>For other platforms, including Mac OS X (Darwin), FreeBSD and
-other Linux distributions, you can download a binary tarball that
-contains Nix and all its dependencies.  (This is what the install
-script at <uri>https://nixos.org/nix/install</uri> uses.)  You should
-unpack it somewhere (e.g. in <filename>/tmp</filename>), and then run
-the script named <command>install</command> inside the binary tarball:
-
-<screen>
-alice$ cd /tmp
-alice$ tar xfj nix-1.7-x86_64-darwin.tar.bz2
-alice$ cd nix-1.7-x86_64-darwin
-alice$ ./install
-</screen>
-
-</para>
-
-<para>Nix can be uninstalled using <command>rpm -e nix</command> or
-<command>dpkg -r nix</command> on RPM- and Dpkg-based systems,
-respectively.  After this you should manually remove the Nix store and
-other auxiliary data, if desired:
-
-<screen>
-$ rm -rf /nix</screen>
-
-</para>
-
-</section>
-
-
-<section><title>Installing Nix from source</title>
-
-<para>If no binary package is available, you can download and compile
-a source distribution.</para>
-
-<section><title>Prerequisites</title>
-
-<itemizedlist>
-
-  <listitem><para>GNU Make.</para></listitem>
-
-  <listitem><para>A version of GCC or Clang that supports C++11.</para></listitem>
-
-  <listitem><para>Perl 5.8 or higher.</para></listitem>
-
-  <listitem><para><command>pkg-config</command> to locate
-  dependencies.  If your distribution does not provide it, you can get
-  it from <link
-  xlink:href="http://www.freedesktop.org/wiki/Software/pkg-config"
-  />.</para></listitem>
-
-  <listitem><para>The bzip2 compressor program and the
-  <literal>libbz2</literal> library.  Thus you must have bzip2
-  installed, including development headers and libraries.  If your
-  distribution does not provide these, you can obtain bzip2 from <link
-  xlink:href="http://www.bzip.org/"/>.</para></listitem>
-
-  <listitem><para>The SQLite embedded database library, version 3.6.19
-  or higher.  If your distribution does not provide it, please install
-  it from <link xlink:href="http://www.sqlite.org/" />.</para></listitem>
-
-  <listitem><para>The Perl DBI and DBD::SQLite libraries, which are
-  available from <link
-  xlink:href="http://search.cpan.org/">CPAN</link> if your
-  distribution does not provide them.</para></listitem>
-
-  <listitem><para>The <link
-  xlink:href="http://www.hpl.hp.com/personal/Hans_Boehm/gc/">Boehm
-  garbage collector</link> to reduce the evaluator’s memory
-  consumption (optional).  To enable it, install
-  <literal>pkgconfig</literal> and the Boehm garbage collector, and
-  pass the flag <option>--enable-gc</option> to
-  <command>configure</command>.</para></listitem>
-
-  <listitem><para>The <command>xmllint</command> and
-  <command>xsltproc</command> programs to build this manual and the
-  man-pages.  These are part of the <literal>libxml2</literal> and
-  <literal>libxslt</literal> packages, respectively.  You also need
-  the <link
-  xlink:href="http://docbook.sourceforge.net/projects/xsl/">DocBook
-  XSL stylesheets</link> and optionally the <link
-  xlink:href="http://www.docbook.org/schemas/5x"> DocBook 5.0 RELAX NG
-  schemas</link>.  Note that these are only required if you modify the
-  manual sources or when you are building from the Git
-  repository.</para></listitem>
-
-  <listitem><para>Recent versions of Bison and Flex to build the
-  parser.  (This is because Nix needs GLR support in Bison and
-  reentrancy support in Flex.)  For Bison, you need version 2.6, which
-  can be obtained from the <link
-  xlink:href="ftp://alpha.gnu.org/pub/gnu/bison">GNU FTP
-  server</link>.  For Flex, you need version 2.5.35, which is
-  available on <link
-  xlink:href="http://lex.sourceforge.net/">SourceForge</link>.
-  Slightly older versions may also work, but ancient versions like the
-  ubiquitous 2.5.4a won't.  Note that these are only required if you
-  modify the parser or when you are building from the Git
-  repository.</para></listitem>
-
-</itemizedlist>
-
-</section>
-
-
-<section><title>Obtaining a source distribution</title>
-
-<para>The source tarball of the most recent stable release can be
-downloaded from the <link
-xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
-You can also grab the <link
-xlink:href="http://hydra.nixos.org/job/nix/trunk/release/latest-finished#tabs-constituents">most
-recent development release</link>.</para>
-
-<para>Alternatively, the most recent sources of Nix can be obtained
-from its <link
-xlink:href="https://github.com/NixOS/nix">Git
-repository</link>.  For example, the following command will check out
-the latest revision into a directory called
-<filename>nix</filename>:</para>
-
-<screen>
-$ git clone https://github.com/NixOS/nix</screen>
-
-<para>Likewise, specific releases can be obtained from the <link
-xlink:href="https://github.com/NixOS/nix/tags">tags</link> of the
-repository.</para>
-
-</section>
-
-
-<section><title>Building Nix from source</title>
-
-<para>After unpacking or checking out the Nix sources, issue the
-following commands:
-
-<screen>
-$ ./configure <replaceable>options...</replaceable>
-$ make
-$ make install</screen>
-
-Nix requires GNU Make so you may need to invoke
-<command>gmake</command> instead.</para>
-
-<para>When building from the Git repository, these should be preceded
-by the command:
-
-<screen>
-$ ./bootstrap.sh</screen>
-
-</para>
-
-<para>The installation path can be specified by passing the
-<option>--prefix=<replaceable>prefix</replaceable></option> to
-<command>configure</command>.  The default installation directory is
-<filename>/usr/local</filename>.  You can change this to any location
-you like.  You must have write permission to the
-<replaceable>prefix</replaceable> path.</para>
-
-<para>Nix keeps its <emphasis>store</emphasis> (the place where
-packages are stored) in <filename>/nix/store</filename> by default.
-This can be changed using
-<option>--with-store-dir=<replaceable>path</replaceable></option>.</para>
-
-<warning><para>It is best <emphasis>not</emphasis> to change the Nix
-store from its default, since doing so makes it impossible to use
-pre-built binaries from the standard Nixpkgs channels — that is, all
-packages will need to be built from source.</para></warning>
-
-<para>Nix keeps state (such as its database and log files) in
-<filename>/nix/var</filename> by default.  This can be changed using
-<option>--localstatedir=<replaceable>path</replaceable></option>.</para>
-
-<para>If you want to rebuild the documentation, pass the full path to
-the DocBook RELAX NG schemas and to the DocBook XSL stylesheets using
-the
-<option>--with-docbook-rng=<replaceable>path</replaceable></option>
-and
-<option>--with-docbook-xsl=<replaceable>path</replaceable></option>
-options.</para>
-
-</section>
-
-
-</section>
-
-
-<!-- TODO: should be updated
-<section><title>Upgrading Nix through Nix</title>
-
-<para>You can install the latest stable version of Nix through Nix
-itself by subscribing to the channel <link
-xlink:href="http://nixos.org/releases/nix/channels/nix-stable" />,
-or the latest unstable version by subscribing to the channel <link
-xlink:href="http://nixos.org/releases/nix/channels/nix-unstable" />.
-You can also do a <link linkend="sec-one-click">one-click
-installation</link> by clicking on the package links at <link
-xlink:href="http://nixos.org/releases/full-index-nix.html" />.</para>
-
-</section>
-->
-
-
-<section><title>Security</title>
-
-<para>Nix has two basic security models.  First, it can be used in
-“single-user mode”, which is similar to what most other package
-management tools do: there is a single user (typically <systemitem
-class="username">root</systemitem>) who performs all package
-management operations.  All other users can then use the installed
-packages, but they cannot perform package management operations
-themselves.</para>
-
-<para>Alternatively, you can configure Nix in “multi-user mode”.  In
-this model, all users can perform package management operations — for
-instance, every user can install software without requiring root
-privileges.  Nix ensures that this is secure.  For instance, it’s not
-possible for one user to overwrite a package used by another user with
-a Trojan horse.</para>
-
-
-<section><title>Single-user mode</title>
-  
-<para>In single-user mode, all Nix operations that access the database
-in <filename><replaceable>prefix</replaceable>/var/nix/db</filename>
-or modify the Nix store in
-<filename><replaceable>prefix</replaceable>/store</filename> must be
-performed under the user ID that owns those directories.  This is
-typically <systemitem class="username">root</systemitem>.  (If you
-install from RPM packages, that’s in fact the default ownership.)
-However, on single-user machines, it is often convenient to
-<command>chown</command> those directories to your normal user account
-so that you don’t have to <command>su</command> to <systemitem
-class="username">root</systemitem> all the time.</para>
-
-</section>
-
-
-<section xml:id="ssec-multi-user"><title>Multi-user mode</title>
-
-<para>To allow a Nix store to be shared safely among multiple users,
-it is important that users are not able to run builders that modify
-the Nix store or database in arbitrary ways, or that interfere with
-builds started by other users.  If they could do so, they could
-install a Trojan horse in some package and compromise the accounts of
-other users.</para>
-
-<para>To prevent this, the Nix store and database are owned by some
-privileged user (usually <literal>root</literal>) and builders are
-executed under special user accounts (usually named
-<literal>nixbld1</literal>, <literal>nixbld2</literal>, etc.).  When a
-unprivileged user runs a Nix command, actions that operate on the Nix
-store (such as builds) are forwarded to a <emphasis>Nix
-daemon</emphasis> running under the owner of the Nix store/database
-that performs the operation.</para>
-
-<note><para>Multi-user mode has one important limitation: only
-<systemitem class="username">root</systemitem> can run <command
-linkend="sec-nix-pull">nix-pull</command> to register the availability
-of pre-built binaries.  However, those registrations are shared by all
-users, so they still get the benefit from <command>nix-pull</command>s
-done by <systemitem class="username">root</systemitem>.</para></note>
-
-
-<section><title>Setting up the build users</title>
-
-<para>The <emphasis>build users</emphasis> are the special UIDs under
-which builds are performed.  They should all be members of the
-<emphasis>build users group</emphasis> (usually called
-<literal>nixbld</literal>).  This group should have no other members.
-The build users should not be members of any other group.</para>
-
-<para>Here is a typical <filename>/etc/group</filename> definition of
-the build users group with 10 build users:
-
-<programlisting>
-nixbld:!:30000:nixbld1,nixbld2,nixbld3,nixbld4,nixbld5,nixbld6,nixbld7,nixbld8,nixbld9,nixbld10
-</programlisting>
-
-In this example the <literal>nixbld</literal> group has UID 30000, but
-of course it can be anything that doesn’t collide with an existing
-group.</para>
-
-<para>Here is the corresponding part of
-<filename>/etc/passwd</filename>:
-
-<programlisting>
-nixbld1:x:30001:65534:Nix build user 1:/var/empty:/noshell
-nixbld2:x:30002:65534:Nix build user 2:/var/empty:/noshell
-nixbld3:x:30003:65534:Nix build user 3:/var/empty:/noshell
-...
-nixbld10:x:30010:65534:Nix build user 10:/var/empty:/noshell
-</programlisting>
-
-The home directory of the build users should not exist or should be an
-empty directory to which they do not have write access.</para>
-
-<para>The build users should have write access to the Nix store, but
-they should not have the right to delete files.  Thus the Nix store’s
-group should be the build users group, and it should have the sticky
-bit turned on (like <filename>/tmp</filename>):
-
-<screen>
-$ chown root.nixbld /nix/store
-$ chmod 1775 /nix/store
-</screen>
-
-</para>
-
-<para>Finally, you should tell Nix to use the build users by
-specifying the build users group in the <link
-linkend="conf-build-users-group"><literal>build-users-group</literal>
-option</link> in the <link linkend="sec-conf-file">Nix configuration
-file</link> (usually <literal>/etc/nix/nix.conf</literal>):
-
-<programlisting>
-build-users-group = nixbld
-</programlisting>
-
-</para>
-
-</section>
-
-
-<section><title>Running the daemon</title>
-
-<para>The <link linkend="sec-nix-daemon">Nix daemon</link> should be
-started as follows (as <literal>root</literal>):
-
-<screen>
-$ nix-daemon</screen>
-
-You’ll want to put that line somewhere in your system’s boot
-scripts.</para>
-
-<para>To let unprivileged users use the daemon, they should set the
-<link linkend="envar-remote"><envar>NIX_REMOTE</envar> environment
-variable</link> to <literal>daemon</literal>.  So you should put a
-line like
-
-<programlisting>
-export NIX_REMOTE=daemon</programlisting>
-
-into the users’ login scripts.</para>
-
-</section>
-
-
-<section><title>Restricting access</title>
-
-<para>To limit which users can perform Nix operations, you can use the
-permissions on the directory
-<filename>/nix/var/nix/daemon-socket</filename>.  For instance, if you
-want to restrict the use of Nix to the members of a group called
-<literal>nix-users</literal>, do
-
-<screen>
-$ chgrp nix-users /nix/var/nix/daemon-socket
-$ chmod ug=rwx,o= /nix/var/nix/daemon-socket
-</screen>
-
-This way, users who are not in the <literal>nix-users</literal> group
-cannot connect to the Unix domain socket
-<filename>/nix/var/nix/daemon-socket/socket</filename>, so they cannot
-perform Nix operations.</para>
-
-</section>
-
-
-</section> <!-- end of multi-user -->
-
-
-</section> <!-- end of security -->
-
-
-<section><title>Using Nix</title>
-
-<para>To use Nix, some environment variables should be set.  In
-particular, <envar>PATH</envar> should contain the directories
-<filename><replaceable>prefix</replaceable>/bin</filename> and
-<filename>~/.nix-profile/bin</filename>.  The first directory contains
-the Nix tools themselves, while <filename>~/.nix-profile</filename> is
-a symbolic link to the current <emphasis>user environment</emphasis>
-(an automatically generated package consisting of symlinks to
-installed packages).  The simplest way to set the required environment
-variables is to include the file
-<filename><replaceable>prefix</replaceable>/etc/profile.d/nix.sh</filename>
-in your <filename>~/.profile</filename> (or similar), like this:</para>
-
-<screen>
-source <replaceable>prefix</replaceable>/etc/profile.d/nix.sh</screen>
-
-</section>
-
-
-</chapter>
@@ -0,0 +1,49 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-building-source">
+
+<title>Building Nix from Source</title>
+
+<para>After unpacking or checking out the Nix sources, issue the
+following commands:
+
+<screen>
+$ ./configure <replaceable>options...</replaceable>
+$ make
+$ make install</screen>
+
+Nix requires GNU Make so you may need to invoke
+<command>gmake</command> instead.</para>
+
+<para>When building from the Git repository, these should be preceded
+by the command:
+
+<screen>
+$ ./bootstrap.sh</screen>
+
+</para>
+
+<para>The installation path can be specified by passing the
+<option>--prefix=<replaceable>prefix</replaceable></option> to
+<command>configure</command>.  The default installation directory is
+<filename>/usr/local</filename>.  You can change this to any location
+you like.  You must have write permission to the
+<replaceable>prefix</replaceable> path.</para>
+
+<para>Nix keeps its <emphasis>store</emphasis> (the place where
+packages are stored) in <filename>/nix/store</filename> by default.
+This can be changed using
+<option>--with-store-dir=<replaceable>path</replaceable></option>.</para>
+
+<warning><para>It is best <emphasis>not</emphasis> to change the Nix
+store from its default, since doing so makes it impossible to use
+pre-built binaries from the standard Nixpkgs channels — that is, all
+packages will need to be built from source.</para></warning>
+
+<para>Nix keeps state (such as its database and log files) in
+<filename>/nix/var</filename> by default.  This can be changed using
+<option>--localstatedir=<replaceable>path</replaceable></option>.</para>
+
+</section>
@@ -0,0 +1,24 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-env-variables">
+
+<title>Environment Variables</title>
+
+<para>To use Nix, some environment variables should be set.  In
+particular, <envar>PATH</envar> should contain the directories
+<filename><replaceable>prefix</replaceable>/bin</filename> and
+<filename>~/.nix-profile/bin</filename>.  The first directory contains
+the Nix tools themselves, while <filename>~/.nix-profile</filename> is
+a symbolic link to the current <emphasis>user environment</emphasis>
+(an automatically generated package consisting of symlinks to
+installed packages).  The simplest way to set the required environment
+variables is to include the file
+<filename><replaceable>prefix</replaceable>/etc/profile.d/nix.sh</filename>
+in your <filename>~/.profile</filename> (or similar), like this:</para>
+
+<screen>
+source <replaceable>prefix</replaceable>/etc/profile.d/nix.sh</screen>
+
+</chapter>
@@ -0,0 +1,34 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="chap-installation">
+
+<title>Installation</title>
+
+<partintro>
+<para>This section describes how to install and configure Nix for first-time use.</para>
+</partintro>
+
+<xi:include href="supported-platforms.xml" />
+<xi:include href="installing-binary.xml" />
+<xi:include href="installing-source.xml" />
+<xi:include href="nix-security.xml" />
+<xi:include href="env-variables.xml" />
+
+<!-- TODO: should be updated
+<section><title>Upgrading Nix through Nix</title>
+
+<para>You can install the latest stable version of Nix through Nix
+itself by subscribing to the channel <link
+xlink:href="http://nixos.org/releases/nix/channels/nix-stable" />,
+or the latest unstable version by subscribing to the channel <link
+xlink:href="http://nixos.org/releases/nix/channels/nix-unstable" />.
+You can also do a <link linkend="sec-one-click">one-click
+installation</link> by clicking on the package links at <link
+xlink:href="http://nixos.org/releases/full-index-nix.html" />.</para>
+
+</section>
+-->
+
+</part>
@@ -0,0 +1,100 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-installing-binary">
+
+<title>Installing a Binary Distribution</title>
+
+<para>If you are using Linux or Mac OS X, the easiest way to install
+Nix is to run the following command:
+
+<screen>
+$ bash &lt;(curl https://nixos.org/nix/install)
+</screen>
+
+This will perform a single-user installation of Nix, meaning that
+<filename>/nix</filename> is owned by the invoking user.  You should
+run this under your usual user account, <emphasis>not</emphasis> as
+root.  The script will invoke <command>sudo</command> to create
+<filename>/nix</filename> if it doesn’t already exist.  If you don’t
+have <command>sudo</command>, you should manually create
+<command>/nix</command> first as root, e.g.:
+
+<screen>
+$ mkdir /nix
+$ chown alice /nix
+</screen>
+
+The install script will modify the first writable file from amongst
+<filename>.bash_profile</filename>, <filename>.bash_login</filename>
+and <filename>.profile</filename> to source
+<filename>~/.nix-profile/etc/profile.d/nix.sh</filename>. You can set
+the <command>NIX_INSTALLER_NO_MODIFY_PROFILE</command> environment
+variable before executing the install script to disable this
+behaviour.
+
+</para>
+
+<!--
+<para>You can also manually download and install a binary package.
+Binary packages of the latest stable release are available for Fedora,
+Debian, Ubuntu, Mac OS X and various other systems from the <link
+xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
+You can also get builds of the latest development release from our
+<link
+xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">continuous
+build system</link>.</para>
+
+<para>For Fedora, RPM packages are available.  These can be installed
+or upgraded using <command>rpm -U</command>.  For example,
+
+<screen>
+$ rpm -U nix-1.8-1.i386.rpm</screen>
+
+</para>
+
+<para>For Debian and Ubuntu, you can download a Deb package and
+install it like this:
+
+<screen>
+$ dpkg -i nix_1.8-1_amd64.deb</screen>
+
+</para>
+-->
+
+<para>You can also download a binary tarball that contains Nix and all
+its dependencies.  (This is what the install script at
+<uri>https://nixos.org/nix/install</uri> does automatically.)  You
+should unpack it somewhere (e.g. in <filename>/tmp</filename>), and
+then run the script named <command>install</command> inside the binary
+tarball:
+
+<screen>
+alice$ cd /tmp
+alice$ tar xfj nix-1.8-x86_64-darwin.tar.bz2
+alice$ cd nix-1.8-x86_64-darwin
+alice$ ./install
+</screen>
+
+</para>
+
+<para>Nix can be uninstalled using <command>rpm -e nix</command> or
+<command>dpkg -r nix</command> on RPM- and Dpkg-based systems,
+respectively.  After this you should manually remove the Nix store and
+other auxiliary data, if desired:
+
+<screen>
+$ rm -rf /nix</screen>
+
+</para>
+
+<para>You can uninstall Nix simply by running:
+
+<screen>
+$ rm -rf /nix
+</screen>
+
+</para>
+
+</chapter>
@@ -0,0 +1,16 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-installing-source">
+
+<title>Installing Nix from Source</title>
+
+<para>If no binary package is available, you can download and compile
+a source distribution.</para>
+
+<xi:include href="prerequisites-source.xml" />
+<xi:include href="obtaining-source.xml" />
+<xi:include href="building-source.xml" />
+
+</chapter>
@@ -0,0 +1,135 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-multi-user">
+
+<title>Multi-User Mode</title>
+
+<para>To allow a Nix store to be shared safely among multiple users,
+it is important that users are not able to run builders that modify
+the Nix store or database in arbitrary ways, or that interfere with
+builds started by other users.  If they could do so, they could
+install a Trojan horse in some package and compromise the accounts of
+other users.</para>
+
+<para>To prevent this, the Nix store and database are owned by some
+privileged user (usually <literal>root</literal>) and builders are
+executed under special user accounts (usually named
+<literal>nixbld1</literal>, <literal>nixbld2</literal>, etc.).  When a
+unprivileged user runs a Nix command, actions that operate on the Nix
+store (such as builds) are forwarded to a <emphasis>Nix
+daemon</emphasis> running under the owner of the Nix store/database
+that performs the operation.</para>
+
+<note><para>Multi-user mode has one important limitation: only
+<systemitem class="username">root</systemitem> and a set of trusted
+users specified in <filename>nix.conf</filename> can specify arbitrary
+binary caches. So while unprivileged users may install packages from
+arbitrary Nix expressions, they may not get pre-built
+binaries.</para></note>
+
+
+<simplesect>
+
+<title>Setting up the build users</title>
+
+<para>The <emphasis>build users</emphasis> are the special UIDs under
+which builds are performed.  They should all be members of the
+<emphasis>build users group</emphasis> <literal>nixbld</literal>.
+This group should have no other members.  The build users should not
+be members of any other group. On Linux, you can create the group and
+users as follows:
+
+<screen>
+$ groupadd -r nixbld
+$ for n in $(seq 1 10); do useradd -c "Nix build user $n" \
+    -d /var/empty -g nixbld -G nixbld -M -N -r -s "$(which nologin)" \
+    nixbld$n; done
+</screen>
+
+This creates 10 build users. There can never be more concurrent builds
+than the number of build users, so you may want to increase this if
+you expect to do many builds at the same time.</para>
+
+<para>On Mac OS X, you can create the required group and users by
+running the following script:
+
+<programlisting>
+#! /bin/bash -e
+
+dseditgroup -o create nixbld -q
+
+gid=$(dscl . -read /Groups/nixbld | awk '($1 == "PrimaryGroupID:") {print $2 }')
+
+echo "created nixbld group with gid $gid"
+
+for i in $(seq 1 10); do
+    user=/Users/nixbld$i
+    uid="$((30000 + $i))"
+    dscl . create $user
+    dscl . create $user RealName "Nix build user $i"
+    dscl . create $user PrimaryGroupID "$gid"
+    dscl . create $user UserShell /usr/bin/false
+    dscl . create $user NFSHomeDirectory /var/empty
+    dscl . create $user UniqueID "$uid"
+    dseditgroup -o edit -a nixbld$i -t user nixbld
+    echo "created nixbld$i user with uid $uid"
+done
+</programlisting>
+
+</para>
+
+</simplesect>
+
+
+<simplesect>
+
+<title>Running the daemon</title>
+
+<para>The <link linkend="sec-nix-daemon">Nix daemon</link> should be
+started as follows (as <literal>root</literal>):
+
+<screen>
+$ nix-daemon</screen>
+
+You’ll want to put that line somewhere in your system’s boot
+scripts.</para>
+
+<para>To let unprivileged users use the daemon, they should set the
+<link linkend="envar-remote"><envar>NIX_REMOTE</envar> environment
+variable</link> to <literal>daemon</literal>.  So you should put a
+line like
+
+<programlisting>
+export NIX_REMOTE=daemon</programlisting>
+
+into the users’ login scripts.</para>
+
+</simplesect>
+
+
+<simplesect>
+
+<title>Restricting access</title>
+
+<para>To limit which users can perform Nix operations, you can use the
+permissions on the directory
+<filename>/nix/var/nix/daemon-socket</filename>.  For instance, if you
+want to restrict the use of Nix to the members of a group called
+<literal>nix-users</literal>, do
+
+<screen>
+$ chgrp nix-users /nix/var/nix/daemon-socket
+$ chmod ug=rwx,o= /nix/var/nix/daemon-socket
+</screen>
+
+This way, users who are not in the <literal>nix-users</literal> group
+cannot connect to the Unix domain socket
+<filename>/nix/var/nix/daemon-socket/socket</filename>, so they cannot
+perform Nix operations.</para>
+
+</simplesect>
+
+
+</section>
@@ -0,0 +1,27 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-nix-security">
+
+<title>Security</title>
+
+<para>Nix has two basic security models.  First, it can be used in
+“single-user mode”, which is similar to what most other package
+management tools do: there is a single user (typically <systemitem
+class="username">root</systemitem>) who performs all package
+management operations.  All other users can then use the installed
+packages, but they cannot perform package management operations
+themselves.</para>
+
+<para>Alternatively, you can configure Nix in “multi-user mode”.  In
+this model, all users can perform package management operations — for
+instance, every user can install software without requiring root
+privileges.  Nix ensures that this is secure.  For instance, it’s not
+possible for one user to overwrite a package used by another user with
+a Trojan horse.</para>
+
+<xi:include href="single-user.xml" />
+<xi:include href="multi-user.xml" />
+
+</chapter>
@@ -0,0 +1,30 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-obtaining-source">
+
+<title>Obtaining a Source Distribution</title>
+
+<para>The source tarball of the most recent stable release can be
+downloaded from the <link
+xlink:href="http://nixos.org/nix/download.html">Nix homepage</link>.
+You can also grab the <link
+xlink:href="http://hydra.nixos.org/job/nix/master/release/latest-finished#tabs-constituents">most
+recent development release</link>.</para>
+
+<para>Alternatively, the most recent sources of Nix can be obtained
+from its <link
+xlink:href="https://github.com/NixOS/nix">Git
+repository</link>.  For example, the following command will check out
+the latest revision into a directory called
+<filename>nix</filename>:</para>
+
+<screen>
+$ git clone https://github.com/NixOS/nix</screen>
+
+<para>Likewise, specific releases can be obtained from the <link
+xlink:href="https://github.com/NixOS/nix/tags">tags</link> of the
+repository.</para>
+
+</section>
@@ -0,0 +1,77 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-prerequisites-source">
+
+<title>Prerequisites</title>
+
+<itemizedlist>
+
+  <listitem><para>GNU Make.</para></listitem>
+
+  <listitem><para>A version of GCC or Clang that supports C++11.</para></listitem>
+
+  <listitem><para>Perl 5.8 or higher.</para></listitem>
+
+  <listitem><para><command>pkg-config</command> to locate
+  dependencies.  If your distribution does not provide it, you can get
+  it from <link
+  xlink:href="http://www.freedesktop.org/wiki/Software/pkg-config"
+  />.</para></listitem>
+  
+  <listitem><para>The OpenSSL library to calculate cryptographic hashes.
+  If your distribution does not provide it, you can get it from <link
+  xlink:href="https://www.openssl.org"/>.</para></listitem>
+
+  <listitem><para>The bzip2 compressor program and the
+  <literal>libbz2</literal> library.  Thus you must have bzip2
+  installed, including development headers and libraries.  If your
+  distribution does not provide these, you can obtain bzip2 from <link
+  xlink:href="http://www.bzip.org/"/>.</para></listitem>
+
+  <listitem><para>The SQLite embedded database library, version 3.6.19
+  or higher.  If your distribution does not provide it, please install
+  it from <link xlink:href="http://www.sqlite.org/" />.</para></listitem>
+
+  <listitem><para>The Perl DBI and DBD::SQLite libraries, which are
+  available from <link
+  xlink:href="http://search.cpan.org/">CPAN</link> if your
+  distribution does not provide them.</para></listitem>
+
+  <listitem><para>The <link
+  xlink:href="http://www.hboehm.info/gc/">Boehm
+  garbage collector</link> to reduce the evaluator’s memory
+  consumption (optional).  To enable it, install
+  <literal>pkgconfig</literal> and the Boehm garbage collector, and
+  pass the flag <option>--enable-gc</option> to
+  <command>configure</command>.</para></listitem>
+
+  <listitem><para>The <command>xmllint</command> and
+  <command>xsltproc</command> programs to build this manual and the
+  man-pages.  These are part of the <literal>libxml2</literal> and
+  <literal>libxslt</literal> packages, respectively.  You also need
+  the <link
+  xlink:href="http://docbook.sourceforge.net/projects/xsl/">DocBook
+  XSL stylesheets</link> and optionally the <link
+  xlink:href="http://www.docbook.org/schemas/5x"> DocBook 5.0 RELAX NG
+  schemas</link>.  Note that these are only required if you modify the
+  manual sources or when you are building from the Git
+  repository.</para></listitem>
+
+  <listitem><para>Recent versions of Bison and Flex to build the
+  parser.  (This is because Nix needs GLR support in Bison and
+  reentrancy support in Flex.)  For Bison, you need version 2.6, which
+  can be obtained from the <link
+  xlink:href="ftp://alpha.gnu.org/pub/gnu/bison">GNU FTP
+  server</link>.  For Flex, you need version 2.5.35, which is
+  available on <link
+  xlink:href="http://lex.sourceforge.net/">SourceForge</link>.
+  Slightly older versions may also work, but ancient versions like the
+  ubiquitous 2.5.4a won't.  Note that these are only required if you
+  modify the parser or when you are building from the Git
+  repository.</para></listitem>
+
+</itemizedlist>
+
+</section>
@@ -0,0 +1,21 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-single-user">
+
+<title>Single-User Mode</title>
+
+<para>In single-user mode, all Nix operations that access the database
+in <filename><replaceable>prefix</replaceable>/var/nix/db</filename>
+or modify the Nix store in
+<filename><replaceable>prefix</replaceable>/store</filename> must be
+performed under the user ID that owns those directories.  This is
+typically <systemitem class="username">root</systemitem>.  (If you
+install from RPM packages, that’s in fact the default ownership.)
+However, on single-user machines, it is often convenient to
+<command>chown</command> those directories to your normal user account
+so that you don’t have to <command>su</command> to <systemitem
+class="username">root</systemitem> all the time.</para>
+
+</section>
@@ -0,0 +1,39 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-supported-platforms">
+
+<title>Supported Platforms</title>
+
+<para>Nix is currently supported on the following platforms:
+
+<itemizedlist>
+
+  <listitem><para>Linux (i686, x86_64).</para></listitem>
+
+  <listitem><para>Mac OS X (x86_64).</para></listitem>
+
+  <!--
+  <listitem><para>FreeBSD (only tested on Intel).</para></listitem>
+  -->
+
+  <!--
+  <listitem><para>Windows through <link
+  xlink:href="http://www.cygwin.com/">Cygwin</link>.</para>
+
+  <warning><para>On Cygwin, Nix <emphasis>must</emphasis> be installed
+  on an NTFS partition.  It will not work correctly on a FAT
+  partition.</para></warning>
+
+  </listitem>
+  -->
+
+</itemizedlist>
+
+</para>
+
+<para>Nix is fairly portable, so it should work on most platforms that
+support POSIX threads and have a C++11 compiler.</para>
+
+</chapter>
@@ -1,11 +1,10 @@
 <chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id="chap-introduction">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-about-nix">

-<title>Introduction</title>
-
-
-<section><title>About Nix</title>
+<title>About Nix</title>

 <para>Nix is a <emphasis>purely functional package manager</emphasis>.
 This means that it treats packages like values in purely functional
@@ -17,10 +16,10 @@ store</emphasis>, usually the directory
 subdirectory such as

 <programlisting>
-/nix/store/nlc4z5y1hm8w9s8vm6m1f5hy962xjmp5-firefox-12.0
+/nix/store/b6gvzjyb2pg0kjfwrjmg1vfhh54ad73z-firefox-33.1/
 </programlisting>

-where <literal>nlc4z5…</literal> is a unique identifier for the
+where <literal>b6gvzjyb2pg0…</literal> is a unique identifier for the
 package that captures all its dependencies (it’s a cryptographic hash
 of the package’s build dependency graph).  This enables many powerful
 features.</para>
@@ -63,9 +62,10 @@ directories such as
 so if a package builds correctly on your system, this is because you
 specified the dependency explicitly.</para>

-<para>Runtime dependencies are found by scanning binaries for the hash
-parts of Nix store paths (such as <literal>r8vvq9kq…</literal>).  This
-sounds risky, but it works extremely well.</para>
+<para>Once a package is built, runtime dependencies are found by
+scanning binaries for the hash parts of Nix store paths (such as
+<literal>r8vvq9kq…</literal>).  This sounds risky, but it works
+extremely well.</para>

 </simplesect>

@@ -81,11 +81,6 @@ package won’t be built or downloaded a second time.  At the same time,
 it is not possible for one user to inject a Trojan horse into a
 package that might be used by another user.</para>

-<!--
-<para>More details can be found in Section 3 of our <a
-href="docs/papers.html#securesharing">ASE 2005 paper</a>.</para>
-->
-
 </simplesect>


@@ -167,19 +162,19 @@ library and the compiler) would have to built, at least if they are
 not already in the Nix store.  This is a <emphasis>source deployment
 model</emphasis>.  For most users, building from source is not very
 pleasant as it takes far too long.  However, Nix can automatically
-skip building from source and download a pre-built binary instead if
-it knows about it.  <emphasis>Nix channels</emphasis> provide Nix
-expressions along with pre-built binaries.</para>
-
-<!--
-<para>source deployment model (like <a
-href="http://www.gentoo.org/">Gentoo</a>) and a binary model (like
-RPM)</para>
-->
+skip building from source and instead use a <emphasis>binary
+cache</emphasis>, a web server that provides pre-built binaries. For
+instance, when asked to build
+<literal>/nix/store/b6gvzjyb2pg0…-firefox-33.1</literal> from source,
+Nix would first check if the file
+<uri>https://cache.nixos.org/b6gvzjyb2pg0….narinfo</uri> exists, and
+if so, fetch the pre-built binary referenced from there; otherwise, it
+would fall back to building from source.</para>

 </simplesect>


+<!--
 <simplesect><title>Binary patching</title>

 <para>In addition to downloading binaries automatically if they’re
@@ -188,6 +183,7 @@ package in the Nix store into a new version.  This speeds up
 upgrades.</para>

 </simplesect>
+-->


 <simplesect><title>Nix Packages collection</title>
@@ -199,24 +195,40 @@ collection</emphasis> (Nixpkgs).</para>
 </simplesect>


-<simplesect><title>Service deployment</title>
+<simplesect><title>Managing build environments</title>

-<para>Nix can be used not only for rolling out packages, but also
-complete <emphasis>configurations</emphasis> of services.  This is
-done by treating all the static bits of a service (such as software
-packages, configuration files, control scripts, static web pages,
-etc.) as “packages” that can be built by Nix expressions.  As a
-result, all the features above apply to services as well: for
-instance, you can roll back a web server configuration if a
-configuration change turns out to be undesirable, you can easily have
-multiple instances of a service (e.g., a test and production server),
-and because the whole service is built in a purely functional way from
-a Nix expression, it is repeatable so you can easily reproduce the
-service on another machine.</para>
+<para>Nix is extremely useful for developers as it makes it easy to
+automatically set up the build environment for a package. Given a
+Nix expression that describes the dependencies of your package, the
+command <command>nix-shell</command> will build or download those
+dependencies if they’re not already in your Nix store, and then start
+a Bash shell in which all necessary environment variables (such as
+compiler search paths) are set.</para>
+
+<para>For example, the following command gets all dependencies of the
+Pan newsreader, as described by <link
+xlink:href="https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/newsreaders/pan/default.nix">its
+Nix expression</link>:</para>
+
+<screen>
+$ nix-shell '&lt;nixpkgs>' -A pan
+</screen>
+
+<para>You’re then dropped into a shell where you can edit, build and test
+the package:</para>
+
+<screen>
+[nix-shell]$ tar xf $src
+[nix-shell]$ cd pan-*
+[nix-shell]$ ./configure
+[nix-shell]$ make
+[nix-shell]$ ./pan/gui/pan
+</screen>

 <!--
-<para>You can read more about this in our <a
-href="docs/papers.html#servicecm">SCM-12 paper</a>.</para>
+<para>Since Nix packages are reproducible and have complete dependency
+specifications, Nix makes an excellent basis for <a
+href="[%root%]hydra">a continuous build system</a>.</para>
 -->

 </simplesect>
@@ -224,8 +236,7 @@ href="docs/papers.html#servicecm">SCM-12 paper</a>.</para>

 <simplesect><title>Portability</title>

-<para>Nix should run on most Unix systems, including Linux, FreeBSD and
-Mac OS X.<!-- It is also supported on Windows using Cygwin.--></para>
+<para>Nix runs on Linux and Mac OS X.</para>

 </simplesect>

@@ -235,39 +246,22 @@ Mac OS X.<!-- It is also supported on Windows using Cygwin.--></para>
 <para>NixOS is a Linux distribution based on Nix.  It uses Nix not
 just for package management but also to manage the system
 configuration (e.g., to build configuration files in
-<filename>/etc</filename>).  This means, among other things, that it’s
-possible to easily roll back the entire configuration of the system to
-an earlier state.  Also, users can install software without root
+<filename>/etc</filename>).  This means, among other things, that it
+is easy to roll back the entire configuration of the system to an
+earlier state.  Also, users can install software without root
 privileges.  For more information and downloads, see the <link
 xlink:href="http://nixos.org/">NixOS homepage</link>.</para>

 </simplesect>


-<!-- other features:
+<simplesect><title>License</title>

- build farms
- reproducibility (Nix expressions allows whole configuration to be rebuilt)
+<para>Nix is released under the terms of the <link
+xlink:href="http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html">GNU
+LGPLv2.1 or (at your option) any later version</link>.</para>

-->
-
-</section>
-
-
-<section><title>License</title>
-
-<para>Nix is free software; you can redistribute it and/or modify it
-under the terms of the <link
-xlink:href="http://www.gnu.org/licenses/lgpl.html">GNU Lesser General
-Public License</link> as published by the <link
-xlink:href="http://www.fsf.org/">Free Software Foundation</link>;
-either version 2.1 of the License, or (at your option) any later
-version.  Nix is distributed in the hope that it will be useful, but
-WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.</para>
-
-</section>
+</simplesect>


 </chapter>
@@ -0,0 +1,12 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="chap-introduction">
+
+<title>Introduction</title>
+
+<xi:include href="about-nix.xml" />
+<xi:include href="quick-start.xml" />
+
+</part>
@@ -1,49 +1,51 @@
 <chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id="chap-quick-start">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="chap-quick-start">

 <title>Quick Start</title>

-
 <para>This chapter is for impatient people who don't like reading
 documentation.  For more in-depth information you are kindly referred
-to the following chapters.</para>
+to subsequent chapters.</para>

-<orderedlist>
+<procedure>

-<listitem><para>Install Nix by running the following:
+<step><para>Install single-user Nix by running the following:

 <screen>
-$ bash &lt;(curl https://nixos.org/nix/install)
+$ curl https://nixos.org/nix/install | sh
 </screen>

 This will install Nix in <filename>/nix</filename>. The install script
 will create <filename>/nix</filename> using <command>sudo</command>,
 so make sure you have sufficient rights.  (For other installation
-methods, see <xref linkend="chap-installation"/>.)</para></listitem>
+methods, see <xref linkend="chap-installation"/>.)</para></step>

-<listitem><para>See what installable packages are currently available
+<step><para>See what installable packages are currently available
 in the channel:

 <screen>
 $ nix-env -qa
-docbook-xml-4.2
-firefox-1.0pre-PR-0.10.1
-hello-2.1.1
-libxslt-1.1.0
+docbook-xml-4.3
+docbook-xml-4.5
+firefox-33.0.2
+hello-2.9
+libxslt-1.1.28
 <replaceable>...</replaceable></screen>

-</para></listitem>
+</para></step>

-<listitem><para>Install some packages from the channel:
+<step><para>Install some packages from the channel:

 <screen>
 $ nix-env -i hello <replaceable>...</replaceable> </screen>

 This should download pre-built packages; it should not build them
-locally (if it does, something went wrong).</para></listitem>
+locally (if it does, something went wrong).</para></step>

-<listitem><para>Test that they work:
+<step><para>Test that they work:

 <screen>
 $ which hello
@@ -52,16 +54,38 @@ $ hello
 Hello, world!
 </screen>

-</para></listitem>
+</para></step>

-<listitem><para>Uninstall a package:
+<step><para>Uninstall a package:

 <screen>
 $ nix-env -e hello</screen>

-</para></listitem>
+</para></step>

-<listitem><para>To keep up-to-date with the channel, do:
+<step><para>You can also test a package without installing it:
+
+<screen>
+$ nix-shell -p hello
+</screen>
+
+This builds or downloads GNU Hello and its dependencies, then drops
+you into a Bash shell where the <command>hello</command> command is
+present, all without affecting your normal environment:
+
+<screen>
+[nix-shell:~]$ hello
+Hello, world!
+
+[nix-shell:~]$ exit
+
+$ hello
+hello: command not found
+</screen>
+
+</para></step>
+
+<step><para>To keep up-to-date with the channel, do:

 <screen>
 $ nix-channel --update nixpkgs
@@ -69,28 +93,18 @@ $ nix-env -u '*'</screen>

 The latter command will upgrade each installed package for which there
 is a “newer” version (as determined by comparing the version
-numbers).</para></listitem>
+numbers).</para></step>

-<listitem><para>You can also install specific packages directly from
-your web browser.  For instance, you can go to <link
-xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest"
-/> and click on any link for the individual packages for your
-platform.  Associate <literal>application/nix-package</literal> with
-the program <command>nix-install-package</command>.  A window should
-appear asking you whether it’s okay to install the package.  Say
-<literal>Y</literal>.  The package and all its dependencies will be
-installed.</para></listitem>
-
-<listitem><para>If you're unhappy with the result of a
+<step><para>If you're unhappy with the result of a
 <command>nix-env</command> action (e.g., an upgraded package turned
 out not to work properly), you can go back:

 <screen>
 $ nix-env --rollback</screen>

-</para></listitem>
+</para></step>

-<listitem><para>You should periodically run the Nix garbage collector
+<step><para>You should periodically run the Nix garbage collector
 to get rid of unused packages, since uninstalls or upgrades don't
 actually delete them:

@@ -103,8 +117,8 @@ rollbacks impossible, but also making the packages in those old
 generations available for garbage collection), while the second
 command actually deletes them.-->

-</para></listitem>
+</para></step>

-</orderedlist>
+</procedure>

 </chapter>
@@ -1,3 +1,6 @@
+
+ifeq ($(doc_generate),yes)
+
 XSLTPROC = $(xsltproc) --nonet $(xmlflags) \
  --param section.autolabel 1 \
  --param section.label.includes.component.label 1 \
@@ -6,9 +9,14 @@ XSLTPROC = $(xsltproc) --nonet $(xmlflags) \
  --param toc.section.depth 3 \
  --param admon.style \'\' \
  --param callout.graphics.extension \'.gif\' \
-  --param contrib.inline.enabled 0
+  --param contrib.inline.enabled 0 \
+  --stringparam generate.toc "book toc" \
+  --param keep.relative.image.uris 0

-MANUAL_SRCS := $(wildcard $(d)/*.xml)
+docbookxsl = http://docbook.sourceforge.net/release/xsl-ns/current
+docbookrng = http://docbook.org/xml/5.0/rng/docbook.rng
+
+MANUAL_SRCS := $(call rwildcard, $(d), *.xml)


 # Do XInclude processing / RelaxNG validation
@@ -23,7 +31,7 @@ $(d)/version.txt:
 $(d)/manual.is-valid: $(d)/manual.xmli
 	$(trace-gen) $(XSLTPROC) --novalid --stringparam profile.condition manual \
 	  $(docbookxsl)/profiling/profile.xsl $< 2> /dev/null | \
-	  $(xmllint) --nonet --noout --relaxng $(docbookrng)/docbook.rng -
+	  $(xmllint) --nonet --noout --relaxng $(docbookrng) -
 	@touch $@

 clean-files += $(d)/manual.xmli $(d)/version.txt $(d)/manual.is-valid
@@ -34,17 +42,19 @@ dist-files += $(d)/manual.xmli $(d)/version.txt $(d)/manual.is-valid
 # Generate man pages.
 man-pages := $(foreach n, \
  nix-env.1 nix-build.1 nix-shell.1 nix-store.1 nix-instantiate.1 \
-  nix-collect-garbage.1 nix-push.1 nix-pull.1 \
+  nix-collect-garbage.1 \
  nix-prefetch-url.1 nix-channel.1 \
-  nix-install-package.1 nix-hash.1 nix-copy-closure.1 \
+  nix-hash.1 nix-copy-closure.1 \
  nix.conf.5 nix-daemon.8, \
  $(d)/$(n))

-$(man-pages): $(d)/manual.xmli $(d)/manual.is-valid
-	$(trace-gen) $(XSLTPROC) --stringparam profile.condition manpage \
+$(firstword $(man-pages)): $(d)/manual.xmli $(d)/manual.is-valid
+	$(trace-gen) $(XSLTPROC) --novalid --stringparam profile.condition manpage \
 	  $(docbookxsl)/profiling/profile.xsl $< 2> /dev/null | \
 	  (cd doc/manual && $(XSLTPROC) $(docbookxsl)/manpages/docbook.xsl -)

+$(wordlist 2, $(words $(man-pages)), $(man-pages)): $(firstword $(man-pages))
+
 clean-files += $(d)/*.1 $(d)/*.5 $(d)/*.8

 dist-files += $(man-pages)
@@ -54,7 +64,7 @@ dist-files += $(man-pages)
 $(d)/manual.html: $(d)/manual.xml $(MANUAL_SRCS) $(d)/manual.is-valid
 	$(trace-gen) $(XSLTPROC) --xinclude --stringparam profile.condition manual \
 	  $(docbookxsl)/profiling/profile.xsl $< | \
-	  $(XSLTPROC) --output $@ $(docbookxsl)/html/docbook.xsl -
+	  $(XSLTPROC) --output $@ $(docbookxsl)/xhtml/docbook.xsl -

 $(foreach file, $(d)/manual.html $(d)/style.css, $(eval $(call install-data-in, $(file), $(docdir)/manual)))

@@ -64,50 +74,14 @@ $(foreach file, $(wildcard $(d)/images/callouts/*.gif), $(eval $(call install-da

 $(eval $(call install-symlink, manual.html, $(docdir)/manual/index.html))

+
 all: $(d)/manual.html

+
+
 clean-files += $(d)/manual.html

 dist-files += $(d)/manual.html


-# Generate the PDF manual.
-$(d)/manual.pdf: $(d)/manual.xml $(MANUAL_SRCS) $(d)/manual.is-valid
-	$(trace-gen) if test "$(dblatex)" != ""; then \
-		cd doc/manual && $(XSLTPROC) --xinclude --stringparam profile.condition manual \
-		  $(docbookxsl)/profiling/profile.xsl manual.xml | \
-		  $(dblatex) -o $(notdir $@) $(dblatex_opts) -; \
-	else \
-		echo "Please install dblatex and rerun configure."; \
-		exit 1; \
-	fi
-
-clean-files += $(d)/manual.pdf
-
-
-# Generate the release notes.
-
-NEWS_OPTS = \
- --stringparam generate.toc "article nop" \
- --stringparam section.autolabel.max.depth 0 \
- --stringparam header.rule 0
-
-$(d)/release-notes.html: $(d)/release-notes.xml
-	$(trace-gen) $(XSLTPROC) --xinclude --output $@ $(NEWS_OPTS) \
-	  $(docbookxsl)/html/docbook.xsl $<
-
-NEWS: $(d)/release-notes.xml
-	$(trace-gen) $(XSLTPROC) --xinclude doc/manual/quote-literals.xsl $< | \
-	  $(XSLTPROC) --output $@.tmp.html $(NEWS_OPTS) \
-	  $(docbookxsl)/html/docbook.xsl - && \
-	LANG=en_US.UTF-8 $(w3m) -dump $@.tmp.html > $@.tmp && \
-	sed -e 's/●/*/g' -e 's/○/-/g' -e 's/━/-/g' < $@.tmp > NEWS && \
-	rm $@.tmp $@.tmp.html
-
-dist-files += NEWS $(d)/release-notes.html
-
-clean-files += NEWS $(d)/release-notes.html
-
-all: $(d)/release-notes.html NEWS
-
-$(foreach file, $(d)/release-notes.html, $(eval $(call install-data-in, $(file), $(docdir)/manual)))
+endif
@@ -1,11 +1,11 @@
 <book xmlns="http://docbook.org/ns/docbook"
-      xmlns:xi="http://www.w3.org/2001/XInclude">
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0">

  <info>
-
-    <title>Nix User's Guide</title>
-
-    <edition>Version <xi:include href="version.txt" parse="text" /></edition>
+    <title>Nix Package Manager Guide</title>
+    <subtitle>Version <xi:include href="version.txt" parse="text" /></subtitle>

    <author>
      <personname>
@@ -19,66 +19,39 @@
    </author>

    <copyright>
-      <year>2004-2013</year>
+      <year>2004-2014</year>
      <holder>Eelco Dolstra</holder>
    </copyright>

-    <date>July 2013</date>
+    <date>November 2014</date>

  </info>

+  <!--
+  <preface>
+    <title>Preface</title>
+    <para>This manual describes how to set up and use the Nix package
+    manager.</para>
+  </preface>
+  -->

-  <xi:include href="introduction.xml" />
-  <xi:include href="quick-start.xml" />
-  <xi:include href="installation.xml" />
-  <xi:include href="package-management.xml" />
-  <xi:include href="writing-nix-expressions.xml" />
-  <xi:include href="build-farm.xml" />
-
-
-  <appendix>
-    <title>Command Reference</title>
-    <xi:include href="opt-common.xml" />
-    <xi:include href="env-common.xml" />
-
-    <section>
-      <title>Main commands</title>
-      <xi:include href="nix-env.xml" />
-      <xi:include href="nix-build.xml" />
-      <xi:include href="nix-shell.xml" />
-      <xi:include href="nix-store.xml" />
-    </section>
-
-    <section>
-      <title>Utilities</title>
-      <xi:include href="nix-channel.xml" />
-      <xi:include href="nix-collect-garbage.xml" />
-      <xi:include href="nix-copy-closure.xml" />
-      <xi:include href="nix-daemon.xml" />
-      <xi:include href="nix-hash.xml" />
-      <xi:include href="nix-install-package.xml" />
-      <xi:include href="nix-instantiate.xml" />
-      <xi:include href="nix-prefetch-url.xml" />
-      <xi:include href="nix-pull.xml" />
-      <xi:include href="nix-push.xml" />
-    </section>
-
-    <section>
-      <title>Files</title>
-      <xi:include href="conf-file.xml" />
-    </section>
-
-  </appendix>
-
-  <xi:include href="troubleshooting.xml" />
-  <!-- <xi:include href="bugs.xml" /> -->
-  <xi:include href="glossary.xml" />
+  <xi:include href="introduction/introduction.xml" />
+  <xi:include href="installation/installation.xml" />
+  <xi:include href="packages/package-management.xml" />
+  <xi:include href="expressions/writing-nix-expressions.xml" />
+  <xi:include href="advanced-topics/advanced-topics.xml" />
+  <xi:include href="command-ref/command-ref.xml" />
+  <xi:include href="troubleshooting/troubleshooting.xml" />
+  <xi:include href="glossary/glossary.xml" />
  <xi:include href="hacking.xml" />
+  <xi:include href="release-notes/release-notes.xml" />

-  <appendix>
+<!--
+<appendix>
    <title>Nix Release Notes</title>
-    <xi:include href="release-notes.xml"
+    <xi:include href="release-notes/release-notes.xml"
                xpointer="xmlns(x=http://docbook.org/ns/docbook)xpointer(x:article/x:section)" />
  </appendix>
+-->

 </book>
@@ -1,112 +0,0 @@
-<refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-channel">
-  
-<refmeta>
-  <refentrytitle>nix-channel</refentrytitle>
-  <manvolnum>1</manvolnum>
-  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
-</refmeta>
-
-<refnamediv>
-  <refname>nix-channel</refname>
-  <refpurpose>manage Nix channels</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
-  <cmdsynopsis>
-    <command>nix-channel</command>
-    <group choice='req'>
-      <arg choice='plain'><option>--add</option> <replaceable>url</replaceable> <arg choice='opt'><replaceable>name</replaceable></arg></arg>
-      <arg choice='plain'><option>--remove</option> <replaceable>url</replaceable></arg>
-      <arg choice='plain'><option>--list</option></arg>
-      <arg choice='plain'><option>--update</option> <arg rep='repeat'><replaceable>names</replaceable></arg></arg>
-    </group>
-  </cmdsynopsis>
-</refsynopsisdiv>
-
-<refsection><title>Description</title>
-
-<para>A Nix channel is mechanism that allows you to automatically stay
-up-to-date with a set of pre-built Nix expressions.  A Nix channel is
-just a URL that points to a place containing a set of Nix expressions
-and a <command>nix-push</command> manifest.  <phrase
-condition="manual">See also <xref linkend="sec-channels"
-/>.</phrase></para>
-
-<para>This command has the following operations:
-
-<variablelist>
-
-  <varlistentry><term><option>--add</option> <replaceable>url</replaceable> [<replaceable>name</replaceable>]</term>
-
-    <listitem><para>Adds a channel named
-    <replaceable>name</replaceable> with URL
-    <replaceable>url</replaceable> to the list of subscribed channels.
-    If <replaceable>name</replaceable> is omitted, it defaults to the
-    last component of <replaceable>url</replaceable>, with the
-    suffixes <literal>-stable</literal> or
-    <literal>-unstable</literal> removed.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--remove</option> <replaceable>name</replaceable></term>
-
-    <listitem><para>Removes the channel named
-    <replaceable>name</replaceable> from the list of subscribed
-    channels.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--list</option></term>
-
-    <listitem><para>Prints the names and URLs of all subscribed
-    channels on standard output.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--update</option> [<replaceable>names</replaceable>…]</term>
-
-    <listitem><para>Downloads the Nix expressions of all subscribed
-    channels (or only those included in
-    <replaceable>names</replaceable> if specified), makes them the
-    default for <command>nix-env</command> operations (by symlinking
-    them from the directory <filename>~/.nix-defexpr</filename>), and
-    performs a <command>nix-pull</command> on the manifests of all
-    channels to make pre-built binaries available.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-</para>
-
-<para>Note that <option>--add</option> does not automatically perform
-an update.</para>
-
-<para>The list of subscribed channels is stored in
-<filename>~/.nix-channels</filename>.</para>
-
-<para>A channel consists of two elements: a bzipped Tar archive
-containing the Nix expressions, and a manifest created by
-<command>nix-push</command>.  These must be stored under
-<literal><replaceable>url</replaceable>/nixexprs.tar.bz2</literal> and
-<literal><replaceable>url</replaceable>/MANIFEST</literal>,
-respectively.</para>
-
-</refsection>
-
-<refsection><title>Examples</title>
-
-<para>To subscribe to the Nixpkgs channel and install the GNU Hello package:</para>
-
-<screen>
-$ nix-channel --add http://nixos.org/channels/nixpkgs-unstable
-$ nix-channel --update
-$ nix-env -iA nixpkgs.hello</screen>
-
-</refsection>
-
-</refentry>
@@ -1,198 +0,0 @@
-<refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-install-package">
-  
-<refmeta>
-  <refentrytitle>nix-install-package</refentrytitle>
-  <manvolnum>1</manvolnum>
-  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
-</refmeta>
-
-<refnamediv>
-  <refname>nix-install-package</refname>
-  <refpurpose>install a Nix Package file</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
-  <cmdsynopsis>
-    <command>nix-install-package</command>
-    <arg><option>--non-interactive</option></arg>
-    <arg>
-      <group choice='req'>
-        <arg choice='plain'><option>--profile</option></arg>
-        <arg choice='plain'><option>-p</option></arg>
-      </group>
-      <replaceable>path</replaceable>
-    </arg>
-    <sbr />
-    <group choice='req'>
-      <arg choice='req'>
-        <option>--url</option>
-        <arg choice='plain'><replaceable>url</replaceable></arg>
-      </arg>
-      <arg choice='req'>
-        <arg choice='plain'><replaceable>file</replaceable></arg>
-      </arg>
-    </group>
-  </cmdsynopsis>
-</refsynopsisdiv>
-
-
-<refsection><title>Description</title>
-
-<para>The command <command>nix-install-package</command> interactively
-installs a Nix Package file (<filename>*.nixpkg</filename>), which is
-a small file that contains a store path to be installed along with the
-URL of a <link linkend="sec-nix-push"><command>nix-push</command>
-manifest</link>.  The Nix Package file is either
-<replaceable>file</replaceable>, or automatically downloaded from
-<replaceable>url</replaceable> if the <option>--url</option> switch is
-used.</para>
-
-<para><command>nix-install-package</command> is used in <link
-linkend="sec-one-click">one-click installs</link> to download and
-install pre-built binary packages with all necessary dependencies.
-<command>nix-install-package</command> is intended to be associated
-with the MIME type <literal>application/nix-package</literal> in a web
-browser so that it is invoked automatically when you click on
-<filename>*.nixpkg</filename> files.  When invoked, it restarts itself
-in a terminal window (since otherwise it would be invisible when run
-from a browser), asks the user to confirm whether to install the
-package, and if so downloads and installs the package into the user’s
-current profile.</para>
-
-<para>To obtain a window, <command>nix-install-package</command> tries
-to restart itself with <command>xterm</command>,
-<command>konsole</command> and
-<command>gnome-terminal</command>.</para>
-
-</refsection>
-
-
-<refsection><title>Options</title>
-
-<variablelist>
-  
-  <varlistentry><term><option>--non-interactive</option></term>
-
-    <listitem><para>Do not open a new terminal window and do not ask
-    for confirmation.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--profile</option></term>
-    <term><option>-p</option></term>
-
-    <listitem><para>Install the package into the specified profile
-    rather than the user’s current profile.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-</refsection>
-
-
-<refsection><title>Examples</title>
-
-<para>To install <filename>subversion-1.4.0.nixpkg</filename> into the
-user’s current profile, without any prompting:
-
-<screen>
-$ nix-install-package --non-interactive subversion-1.4.0.nixpkg</screen>
-
-</para>
-
-<para>To install the same package from some URL into a different
-profile:
-
-<screen>
-$ nix-install-package --non-interactive -p /nix/var/nix/profiles/eelco \
-    --url http://nix.cs.uu.nl/dist/nix/nixpkgs-0.10pre6622/pkgs/subversion-1.4.0-i686-linux.nixpkg</screen>
-
-</para>
-
-</refsection>
-
-
-<refsection><title>Format of <literal>nixpkg</literal> files</title>
-
-<para>A Nix Package file consists of a single line with the following
-format:
-
-<screen>
-NIXPKG1 <replaceable>manifestURL</replaceable> <replaceable>name</replaceable> <replaceable>system</replaceable> <replaceable>drvPath</replaceable> <replaceable>outPath</replaceable></screen>
-
-The elemens are as follows:
-
-<variablelist>
-
-  <varlistentry><term><literal>NIXPKG1</literal></term>
-  
-    <listitem><para>The version of the Nix Package
-    file.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><replaceable>manifestURL</replaceable></term>
-  
-    <listitem><para>The manifest to be pulled by
-    <command>nix-pull</command>.  The manifest must contain
-    <replaceable>outPath</replaceable>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><replaceable>name</replaceable></term>
-  
-    <listitem><para>The symbolic name and version of the
-    package.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><replaceable>system</replaceable></term>
-  
-    <listitem><para>The platform identifier of the platform for which
-    this binary package is intended.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><replaceable>drvPath</replaceable></term>
-  
-    <listitem><para>The path in the Nix store of the derivation from
-    which <replaceable>outPath</replaceable> was built.  Not currently
-    used.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><replaceable>outPath</replaceable></term>
-  
-    <listitem><para>The path in the Nix store of the package.  After
-    <command>nix-install-package</command> has obtained the manifest
-    from <replaceable>manifestURL</replaceable>, it performs a
-    <literal>nix-env -i</literal> <replaceable>outPath</replaceable>
-    to install the binary package.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-  
-</para>
-
-<para>An example follows:
-
-<screen>
-NIXPKG1 http://.../nixpkgs-0.10pre6622/MANIFEST subversion-1.4.0 i686-darwin \
-  /nix/store/4kh60jkp...-subversion-1.4.0.drv \
-  /nix/store/nkw7wpgb...-subversion-1.4.0</screen>
-
-(The line breaks (<literal>\</literal>) are for presentation purposes
-and not part of the actual file.)
-
-</para>
-
-</refsection>
-
-
-</refentry>
@@ -1,50 +0,0 @@
-<refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-pull">
-
-<refmeta>
-  <refentrytitle>nix-pull</refentrytitle>
-  <manvolnum>1</manvolnum>
-  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
-</refmeta>
-
-<refnamediv>
-  <refname>nix-pull</refname>
-  <refpurpose>pull substitutes from a network cache</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
-  <cmdsynopsis>
-    <command>nix-pull</command>
-    <arg choice='plain'><replaceable>url</replaceable></arg>
-  </cmdsynopsis>
-</refsynopsisdiv>
-
-
-<refsection><title>Description</title>
-
-<para>The command <command>nix-pull</command> obtains a list of
-pre-built store paths from the URL <replaceable>url</replaceable>, and
-for each of these store paths, registers a substitute derivation that
-downloads and unpacks it into the Nix store.  This is used to speed up
-installations: if you attempt to install something that has already
-been built and stored into the network cache, Nix can transparently
-re-use the pre-built store paths.</para>
-
-<para>The file at <replaceable>url</replaceable> must be compatible
-with the files created by <replaceable>nix-push</replaceable>.</para>
-
-</refsection>
-
-
-<refsection><title>Examples</title>
-
-<screen>
-$ nix-pull http://nix.cs.uu.nl/dist/nix/nixpkgs-0.5pre753/MANIFEST</screen>
-
-</refsection>
-
-
-</refentry>
@@ -1,398 +0,0 @@
-<refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-push">
-
-<refmeta>
-  <refentrytitle>nix-push</refentrytitle>
-  <manvolnum>1</manvolnum>
-  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
-</refmeta>
-
-<refnamediv>
-  <refname>nix-push</refname>
-  <refpurpose>generate a binary cache</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
-  <cmdsynopsis>
-    <command>nix-push</command>
-    <arg choice='plain'><option>--dest</option> <replaceable>dest-dir</replaceable></arg>
-    <arg><option>--bzip2</option></arg>
-    <arg><option>--none</option></arg>
-    <arg><option>--force</option></arg>
-    <arg><option>--link</option></arg>
-    <arg><option>--manifest</option></arg>
-    <arg><option>--manifest-path</option> <replaceable>filename</replaceable></arg>
-    <arg><option>--url-prefix</option> <replaceable>url</replaceable></arg>
-    <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
-  </cmdsynopsis>
-</refsynopsisdiv>
-
-
-<refsection><title>Description</title>
-
-<para>The command <command>nix-push</command> produces a
-<emphasis>binary cache</emphasis>, a directory containing compressed
-Nix archives (NARs) plus some metadata of the closure of the specified
-store paths.  This directory can then be made available through a web
-server to other Nix installations, allowing them to skip building from
-source and instead download binaries from the cache
-automatically.</para>
-
-<para><command>nix-push</command> performs the following actions.
-      
-<orderedlist>
-
-  <listitem><para>Each path in <replaceable>paths</replaceable> is
-  built (using <link
-  linkend='rsec-nix-store-realise'><command>nix-store
-  --realise</command></link>).</para></listitem>
-
-  <listitem><para>All paths in the closure of
-  <replaceable>paths</replaceable> are determined (using
-  <command>nix-store --query --requisites
-  --include-outputs</command>).  Note that since the
-  <option>--include-outputs</option> flag is used, if
-  <replaceable>paths</replaceable> includes a store derivation, you
-  get a combined source/binary distribution (e.g., source tarballs
-  will be included).</para></listitem>
-
-  <listitem><para>All store paths determined in the previous step are
-  packaged into a NAR (using <command>nix-store --dump</command>) and
-  compressed using <command>xz</command> or <command>bzip2</command>.
-  The resulting files have the extension <filename>.nar.xz</filename>
-  or <filename>.nar.bz2</filename>.  Also for each store path, Nix
-  generates a file with extension <filename>.narinfo</filename>
-  containing metadata such as the references, cryptographic hash and
-  size of each path.</para></listitem>
-
-  <listitem><para>Optionally, a single <emphasis>manifest</emphasis>
-  file is created that contains the same metadata as the
-  <filename>.narinfo</filename> files.  This is for compatibility with
-  Nix versions prior to 1.2 (see <command>nix-pull</command> for
-  details).</para></listitem>
-
-  <listitem><para>A file named <option>nix-cache-info</option> is
-  placed in the destination directory.  The existence of this file
-  marks the directory as a binary cache.</para></listitem>
-
-</orderedlist>
-
-</para>
-
-</refsection>
-
-
-<refsection><title>Options</title>
-
-<variablelist>
-
-  <varlistentry><term><option>--dest</option> <replaceable>dest-dir</replaceable></term>
-
-    <listitem><para>Set the destination directory to
-    <replaceable>dir</replaceable>, which is created if it does not
-    exist.  This flag is required.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--bzip2</option></term>
-
-    <listitem><para>Compress NARs using <command>bzip2</command>
-    instead of <command>xz -9</command>.  The latter compresses about
-    30% better on typical archives, decompresses about twice as fast,
-    but compresses a lot slower and is not supported by Nix prior to
-    version 1.2.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--none</option></term>
-
-    <listitem><para>Do not compress NARs.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--force</option></term>
-
-    <listitem><para>Overwrite <filename>.narinfo</filename> files if
-    they already exist.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--link</option></term>
-
-    <listitem><para>By default, NARs are generated in the Nix store
-    and then copied to <replaceable>dest-dir</replaceable>.  If this
-    option is given, hard links are used instead.  This only works if
-    <replaceable>dest-dir</replaceable> is on the same filesystem as
-    the Nix store.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--manifest</option></term>
-
-    <listitem><para>Force the generation of a manifest suitable for
-    use by <command>nix-pull</command>.  The manifest is stored as
-    <filename><replaceable>dest-dir</replaceable>/MANIFEST</filename>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--manifest-path</option> <replaceable>filename</replaceable></term>
-
-    <listitem><para>Like <option>--manifest</option>, but store the
-    manifest in <replaceable>filename</replaceable>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--url-prefix</option> <replaceable>url</replaceable></term>
-
-    <listitem><para>Manifests are expected to contain the absolute
-    URLs of NARs.  For generating these URLs, the prefix
-    <replaceable>url</replaceable> is used.  It defaults to
-    <uri>file://<replaceable>dest-dir</replaceable></uri>.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-</refsection>
-
-
-<refsection><title>Examples</title>
-
-<para>To add the closure of Thunderbird to a binary cache:
-
-<screen>
-$ nix-push --dest /tmp/cache $(nix-build -A thunderbird)
-</screen>
-
-Assuming that <filename>/tmp/cache</filename> is exported by a web
-server as <uri>http://example.org/cache</uri>, you can then use this
-cache on another machine to speed up the installation of Thunderbird:
-
-<screen>
-$ nix-build -A thunderbird --option binary-caches http://example.org/cache
-</screen>
-
-Alternatively, you could add <literal>binary-caches =
-http://example.org/cache</literal> to
-<filename>nix.conf</filename>.</para>
-
-<para>To also include build-time dependencies (such as source
-tarballs):
-
-<screen>
-$ nix-push --dest /tmp/cache $(nix-instantiate -A thunderbird)
-</screen>
-
-</para>
-
-<para>To generate a manifest suitable for <command>nix-pull</command>:
-
-<screen>
-$ nix-push --dest /tmp/cache $(nix-build -A thunderbird) --manifest
-</screen>
-
-On another machine you can then do:
-
-<screen>
-$ nix-pull http://example.org/cache
-</screen>
-
-to cause the binaries to be used by subsequent Nix operations.</para>
-
-</refsection>
-
-
-<refsection><title>Binary cache format and operation</title>
-
-<para>A binary cache with URL <replaceable>url</replaceable> only
-denotes a valid binary cache if the file
-<uri><replaceable>url</replaceable>/nix-cache-info</uri> exists.  If
-this file does not exist (or cannot be downloaded), the cache is
-ignored.  If it does exist, it must be a text file containing cache
-properties.  Here’s an example:
-
-<screen>
-StoreDir: /nix/store
-WantMassQuery: 1
-Priority: 10
-</screen>
-
-The properties that are currently supported are:
-
-<variablelist>
-  
-  <varlistentry><term><literal>StoreDir</literal></term>
-
-    <listitem><para>The path of the Nix store to which this binary
-    cache applies.  Binaries are not relocatable — a binary built for
-    <filename>/nix/store</filename> won’t generally work in
-    <filename>/home/alice/store</filename> — so to prevent binaries
-    from being used in a wrong store, a binary cache is only used if
-    its <literal>StoreDir</literal> matches the local Nix
-    configuration.  The default is
-    <filename>/nix/store</filename>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>WantMassQuery</literal></term>
-
-    <listitem><para>Query operations such as <command>nix-env
-    -qas</command> can cause thousands of cache queries, and thus
-    thousands of HTTP requests, to determine which packages are
-    available in binary form.  While these requests are small, not
-    every server may appreciate a potential onslaught of queries.  If
-    <literal>WantMassQuery</literal> is set to <literal>0</literal>
-    (default), “mass queries” such as <command>nix-env -qas</command>
-    will skip this cache.  Thus a package may appear not to have a
-    binary substitute.  However, the binary will still be used when
-    you actually install the package.  If
-    <literal>WantMassQuery</literal> is set to <literal>1</literal>,
-    mass queries will use this cache.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>Priority</literal></term>
-
-    <listitem><para>Each binary cache has a priority (defaulting to
-    50).  Binary caches are checked for binaries in order of ascending
-    priority; thus a higher number denotes a lower priority.  The
-    binary cache <uri>http://cache.nixos.org</uri> has priority
-    40.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-</para>
-
-<para>Every time Nix needs to build some store path
-<replaceable>p</replaceable>, it will check each configured binary
-cache to see if it has a NAR file for <replaceable>p</replaceable>,
-until it finds one.  If no cache has a NAR, Nix will fall back to
-building the path from source (if applicable).  To see if a cache with
-URL <replaceable>url</replaceable> has a binary for
-<replaceable>p</replaceable>, Nix fetches
-<replaceable>url/h</replaceable>, where <replaceable>h</replaceable>
-is the hash part of <replaceable>p</replaceable>.  Thus, if we have a
-cache <uri>http://cache.nixos.org</uri> and we want to obtain
-the store path
-<screen>
-/nix/store/a8922c0h87iilxzzvwn2hmv8x210aqb9-glibc-2.7
-</screen>
-then Nix will attempt to fetch
-<screen>
-http://cache.nixos.org/a8922c0h87iilxzzvwn2hmv8x210aqb9.narinfo
-</screen>
-(Commands such as <command>nix-env -qas</command> will issue an HTTP
-HEAD request, since it only needs to know if the
-<filename>.narinfo</filename> file exists.)  The
-<filename>.narinfo</filename> file is a simple text file that looks
-like this:
-
-<screen>
-StorePath: /nix/store/a8922c0h87iilxzzvwn2hmv8x210aqb9-glibc-2.7
-URL: nar/0zzjpdz46mdn74v09m053yczlz4am038g8r74iy8w43gx8801h70.nar.bz2
-Compression: bzip2
-FileHash: sha256:0zzjpdz46mdn74v09m053yczlz4am038g8r74iy8w43gx8801h70
-FileSize: 24473768
-NarHash: sha256:0s491y1h9hxj5ghiizlxk7ax6jwbha00zwn7lpyd5xg5bhf60vzg
-NarSize: 109521136
-References: 2ma2k0ys8knh4an48n28vigcmc2z8773-linux-headers-2.6.23.16 ...
-Deriver: 7akyyc87ka32xwmqza9dvyg5pwx3j212-glibc-2.7.drv
-</screen>
-
-The fields are as follows:
-
-<variablelist>
-  
-  <varlistentry><term><literal>StorePath</literal></term>
-
-    <listitem><para>The full store path, including the name part
-    (e.g., <literal>glibc-2.7</literal>).  It must match the
-    requested store path.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>URL</literal></term>
-
-    <listitem><para>The URL of the NAR, relative to the binary cache
-    URL.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>Compression</literal></term>
-
-    <listitem><para>The compression method; either
-    <literal>xz</literal> or
-    <literal>bzip2</literal>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>FileHash</literal></term>
-
-    <listitem><para>The SHA-256 hash of the compressed
-    NAR.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>FileSize</literal></term>
-
-    <listitem><para>The size of the compressed NAR.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>NarHash</literal></term>
-
-    <listitem><para>The SHA-256 hash of the uncompressed NAR.  This is
-    equal to the hash of the store path as returned by
-    <command>nix-store -q --hash
-    <replaceable>p</replaceable></command>.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>NarSize</literal></term>
-
-    <listitem><para>The size of the uncompressed NAR.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>References</literal></term>
-
-    <listitem><para>The references of the store path, without the Nix
-    store prefix.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>Deriver</literal></term>
-
-    <listitem><para>The deriver of the store path, without the Nix
-    store prefix.  This field is optional.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><literal>System</literal></term>
-
-    <listitem><para>The Nix platform type of this binary, if known.
-    This field is optional.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-</para>
-
-<para>Thus, in our example, after recursively ensuring that the
-references exist (e.g.,
-<filename>/nix/store/2ma2k0ys8knh4an48n28vigcmc2z8773-linux-headers-2.6.23.16</filename>),
-Nix will fetch <screen>
-http://cache.nixos.org/nar/0zzjpdz46mdn74v09m053yczlz4am038g8r74iy8w43gx8801h70.nar.bz2
-</screen> and decompress and unpack it to
-<filename>/nix/store/a8922c0h87iilxzzvwn2hmv8x210aqb9-glibc-2.7</filename>.</para>
-
-</refsection>
-
-
-</refentry>
@@ -1,200 +0,0 @@
-<refentry xmlns="http://docbook.org/ns/docbook"
-          xmlns:xlink="http://www.w3.org/1999/xlink"
-          xmlns:xi="http://www.w3.org/2001/XInclude"
-          xml:id="sec-nix-shell">
-
-<refmeta>
-  <refentrytitle>nix-shell</refentrytitle>
-  <manvolnum>1</manvolnum>
-  <refmiscinfo class="source">Nix</refmiscinfo>
-  <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo>
-</refmeta>
-
-<refnamediv>
-  <refname>nix-shell</refname>
-  <refpurpose>start an interactive shell based on a Nix expression</refpurpose>
-</refnamediv>
-
-<refsynopsisdiv>
-  <cmdsynopsis>
-    <command>nix-shell</command>
-    <arg><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
-    <arg><option>--argstr</option> <replaceable>name</replaceable> <replaceable>value</replaceable></arg>
-    <arg>
-      <group choice='req'>
-        <arg choice='plain'><option>--attr</option></arg>
-        <arg choice='plain'><option>-A</option></arg>
-      </group>
-      <replaceable>attrPath</replaceable>
-    </arg>
-    <arg><option>--command</option> <replaceable>cmd</replaceable></arg>
-    <arg><option>--exclude</option> <replaceable>regexp</replaceable></arg>
-    <arg><option>--pure</option></arg>
-    <group choice='req'>
-      <group choice='plain'>
-        <group>
-          <arg choice='plain'><option>--packages</option></arg>
-          <arg choice='plain'><option>-p</option></arg>
-        </group>
-        <replaceable>packages</replaceable>
-      </group>
-      <arg><replaceable>path</replaceable></arg>
-    </group>
-  </cmdsynopsis>
-</refsynopsisdiv>
-
-<refsection><title>Description</title>
-
-<para>The command <command>nix-shell</command> will build the
-dependencies of the specified derivation, but not the derivation
-itself.  It will then start an interactive shell in which all
-environment variables defined by the derivation
-<replaceable>path</replaceable> have been set to their corresponding
-values, and the script <literal>$stdenv/setup</literal> has been
-sourced.  This is useful for reproducing the environment of a
-derivation for development.</para>
-
-<para>If <replaceable>path</replaceable> is not given,
-<command>nix-shell</command> defaults to
-<filename>shell.nix</filename> if it exists, and
-<filename>default.nix</filename> otherwise.</para>
-
-<para>If the derivation defines the variable
-<varname>shellHook</varname>, it will be evaluated after
-<literal>$stdenv/setup</literal> has been sourced.  Since this hook is
-not executed by regular Nix builds, it allows you to perform
-initialisation specific to <command>nix-shell</command>.  For example,
-the derivation attribute
-
-<programlisting>
-shellHook =
-  ''
-    echo "Hello shell"
-  '';
-</programlisting>
-
-will cause <command>nix-shell</command> to print <literal>Hello shell</literal>.</para>
-
-</refsection>
-
-
-<refsection><title>Options</title>
-
-<para>All options not listed here are passed to <command>nix-store
--realise</command>, except for <option>--arg</option> and
-<option>--attr</option> / <option>-A</option> which are passed to
-<command>nix-instantiate</command>.  <phrase condition="manual">See
-also <xref linkend="sec-common-options" />.</phrase></para>
-
-<variablelist>
-
-  <varlistentry><term><option>--command</option> <replaceable>cmd</replaceable></term>
-
-    <listitem><para>In the environment of the derivation, run the
-    shell command <replaceable>cmd</replaceable> instead of starting
-    an interactive shell.  However, if you end the shell command with
-    <literal>return</literal>, you still get an interactive shell.
-    This can be useful for doing any additional
-    initialisation.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--exclude</option> <replaceable>regexp</replaceable></term>
-
-    <listitem><para>Do not build any dependencies whose store path
-    matches the regular expression <replaceable>regexp</replaceable>.
-    This option may be specified multiple times.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--pure</option></term>
-
-    <listitem><para>If this flag is specified, the environment is
-    almost entirely cleared before the interactive shell is started,
-    so you get an environment that more closely corresponds to the
-    “real” Nix build.  A few variables, in particular
-    <envar>HOME</envar>, <envar>USER</envar> and
-    <envar>DISPLAY</envar>, are retained.  Note that
-    <filename>~/.bashrc</filename> and (depending on your Bash
-    installation) <filename>/etc/bashrc</filename> are still sourced,
-    so any variables set there will affect the interactive
-    shell.</para></listitem>
-
-  </varlistentry>
-
-  <varlistentry><term><option>--packages</option> / <option>-p</option></term>
-
-    <listitem><para>Set up an environment in which the specified
-    packages are present.  The command line arguments are interpreted
-    as attribute names inside the Nix Packages collection.  Thus,
-    <literal>nix-shell -p libjpeg openjdk</literal> will start a shell
-    in which the packages denoted by the attribute names
-    <varname>libjpeg</varname> and <varname>openjdk</varname> are
-    present.</para></listitem>
-
-  </varlistentry>
-
-</variablelist>
-
-<para>The following common options are supported:</para>
-
-<variablelist condition="manpage">
-  <xi:include href="opt-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='opt-common']/*)" />
-</variablelist>
-
-</refsection>
-
-
-<refsection><title>Examples</title>
-
-<para>To build the dependencies of the package Pan, and start an
-interactive shell in which to build it:
-
-<screen>
-$ nix-shell '&lt;nixpkgs>' -A pan
-[nix-shell]$ unpackPhase
-[nix-shell]$ cd pan-*
-[nix-shell]$ configurePhase
-[nix-shell]$ buildPhase
-[nix-shell]$ ./pan/gui/pan
-</screen>
-
-To clear the environment first, and do some additional automatic
-initialisation of the interactive shell:
-
-<screen>
-$ nix-shell '&lt;nixpkgs>' -A pan --pure \
-    --command 'export NIX_DEBUG=1; export NIX_CORES=8; return'
-</screen>
-
-Nix expressions can also be given on the command line.  For instance,
-the following starts a shell containing the packages
-<literal>sqlite</literal> and <literal>libX11</literal>:
-
-<screen>
-$ nix-shell -E 'with import &lt;nixpkgs> { }; runCommand "dummy" { buildInputs = [ sqlite xorg.libX11 ]; } ""'
-</screen>
-
-A shorter way to do the same is:
-
-<screen>
-$ nix-shell -p sqlite xorg.libX11
-[nix-shell]$ echo $NIX_LDFLAGS
-… -L/nix/store/j1zg5v…-sqlite-3.8.0.2/lib -L/nix/store/0gmcz9…-libX11-1.6.1/lib …
-</screen>
-
-</para>
-
-</refsection>
-
-
-<refsection condition="manpage"><title>Environment variables</title>
-
-<variablelist>
-  <xi:include href="env-common.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(//db:variablelist[@xml:id='env-common']/*)" />
-</variablelist>
-
-</refsection>
-
-
-</refentry>
@@ -1,591 +0,0 @@
-<chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xml:id='chap-package-management'>
-
-<title>Package Management</title>
-
-
-<para>This chapter discusses how to do package management with Nix,
-i.e., how to obtain, install, upgrade, and erase packages.  This is
-the “user’s” perspective of the Nix system — people
-who want to <emphasis>create</emphasis> packages should consult
-<xref linkend='chap-writing-nix-expressions' />.</para>
-
-
-<section><title>Basic package management</title>
-
-<para>The main command for package management is <link
-linkend="sec-nix-env"><command>nix-env</command></link>.  You can use
-it to install, upgrade, and erase packages, and to query what
-packages are installed or are available for installation.</para>
-
-<para>In Nix, different users can have different “views”
-on the set of installed applications.  That is, there might be lots of
-applications present on the system (possibly in many different
-versions), but users can have a specific selection of those active —
-where “active” just means that it appears in a directory
-in the user’s <envar>PATH</envar>.  Such a view on the set of
-installed applications is called a <emphasis>user
-environment</emphasis>, which is just a directory tree consisting of
-symlinks to the files of the active applications.  </para>
-
-<para>Components are installed from a set of <emphasis>Nix
-expressions</emphasis> that tell Nix how to build those packages,
-including, if necessary, their dependencies.  There is a collection of
-Nix expressions called the Nix Package collection that contains
-packages ranging from basic development stuff such as GCC and Glibc,
-to end-user applications like Mozilla Firefox.  (Nix is however not
-tied to the Nix Package collection; you could write your own Nix
-expressions based on it, or completely new ones.)  You can download
-the latest version from <link
-xlink:href='http://nixos.org/nixpkgs/download.html' />.</para>
-
-<para>Assuming that you have downloaded and unpacked a release of Nix
-Packages, you can view the set of available packages in the release:
-
-<screen>
-$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> '*'
-ant-blackdown-1.4.2
-aterm-2.2
-bash-3.0
-binutils-2.15
-bison-1.875d
-blackdown-1.4.2
-bzip2-1.0.2
-...</screen>
-
-where <literal>nixpkgs-<replaceable>version</replaceable></literal> is
-where you’ve unpacked the release.  The flag <option>-q</option>
-specifies a query operation; <option>-a</option> means that you want
-to show the “available” (i.e., installable) packages, as opposed to
-the installed packages; and <option>-f</option>
-<filename>nixpkgs-<replaceable>version</replaceable></filename>
-specifies the source of the packages.  The argument
-<literal>'*'</literal> shows all installable packages. (The quotes are
-necessary to prevent shell expansion.)  You can also select specific
-packages by name:
-
-<screen>
-$ nix-env -qaf nixpkgs-<replaceable>version</replaceable> gcc
-gcc-3.4.6
-gcc-4.0.3
-gcc-4.1.1</screen>
-
-</para>
-
-<para>It is also possible to see the <emphasis>status</emphasis> of
-available packages, i.e., whether they are installed into the user
-environment and/or present in the system:
-
-<screen>
-$ nix-env -qasf nixpkgs-<replaceable>version</replaceable> '*'
-...
-PS bash-3.0
--S binutils-2.15
-IPS bison-1.875d
-...</screen>
-
-The first character (<literal>I</literal>) indicates whether the
-package is installed in your current user environment.  The second
-(<literal>P</literal>) indicates whether it is present on your system
-(in which case installing it into your user environment would be a
-very quick operation).  The last one (<literal>S</literal>) indicates
-whether there is a so-called <emphasis>substitute</emphasis> for the
-package, which is Nix’s mechanism for doing binary deployment.  It
-just means that Nix knows that it can fetch a pre-built package from
-somewhere (typically a network server) instead of building it
-locally.</para>
-
-<para>So now that we have a set of Nix expressions we can build the
-packages contained in them.  This is done using <literal>nix-env
-i</literal>.  For instance,
-
-<screen>
-$ nix-env -f nixpkgs-<replaceable>version</replaceable> -i subversion</screen>
-
-will install the package called <literal>subversion</literal> (which
-is, of course, the <link
-xlink:href='http://subversion.tigris.org/'>Subversion version
-management system</link>).</para>
-
-<para>When you do this for the first time, Nix will start building
-Subversion and all its dependencies.  This will take quite a while —
-typically an hour or two on modern machines.  Fortunately, there is a
-faster way (so do a Ctrl-C on that install operation!): you just need
-to tell Nix that pre-built binaries of all those packages are
-available somewhere.  This is done using the
-<command>nix-pull</command> command, which must be supplied with a URL
-containing a <emphasis>manifest</emphasis> describing what binaries
-are available.  This URL should correspond to the Nix Packages release
-that you’re using.  For instance, if you obtained a release from <link
-xlink:href='http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x'
-/>, then you should do:
-
-<screen>
-$ nix-pull http://nixos.org/releases/nixpkgs/nixpkgs-0.12pre11712-4lrp7j8x/MANIFEST</screen>
-
-If you then issue the installation command, it should start
-downloading binaries from <systemitem
-class='fqdomainname'>nixos.org</systemitem>, instead of building
-them from source.  This might still take a while since all
-dependencies must be downloaded, but on a reasonably fast connection
-such as a DSL line it’s on the order of a few minutes.</para>
-
-<para>Naturally, packages can also be uninstalled:
-
-<screen>
-$ nix-env -e subversion</screen>
-
-</para>
-
-<para>Upgrading to a new version is just as easy.  If you have a new
-release of Nix Packages, you can do:
-
-<screen>
-$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u subversion</screen>
-
-This will <emphasis>only</emphasis> upgrade Subversion if there is a
-“newer” version in the new set of Nix expressions, as
-defined by some pretty arbitrary rules regarding ordering of version
-numbers (which generally do what you’d expect of them).  To just
-unconditionally replace Subversion with whatever version is in the Nix
-expressions, use <parameter>-i</parameter> instead of
-<parameter>-u</parameter>; <parameter>-i</parameter> will remove
-whatever version is already installed.</para>
-
-<para>You can also upgrade all packages for which there are newer
-versions:
-
-<screen>
-$ nix-env -f nixpkgs-<replaceable>version</replaceable> -u '*'</screen>
-
-</para>
-
-<para>Sometimes it’s useful to be able to ask what
-<command>nix-env</command> would do, without actually doing it.  For
-instance, to find out what packages would be upgraded by
-<literal>nix-env -u '*'</literal>, you can do
-
-<screen>
-$ nix-env ... -u '*' --dry-run
-(dry run; not doing anything)
-upgrading `libxslt-1.1.0' to `libxslt-1.1.10'
-upgrading `graphviz-1.10' to `graphviz-1.12'
-upgrading `coreutils-5.0' to `coreutils-5.2.1'</screen>
-
-</para>
-
-</section>
-
-
-<section xml:id="sec-profiles"><title>Profiles</title>
-
-<para>Profiles and user environments are Nix’s mechanism for
-implementing the ability to allow different users to have different
-configurations, and to do atomic upgrades and rollbacks.  To
-understand how they work, it’s useful to know a bit about how Nix
-works.  In Nix, packages are stored in unique locations in the
-<emphasis>Nix store</emphasis> (typically,
-<filename>/nix/store</filename>).  For instance, a particular version
-of the Subversion package might be stored in a directory
-<filename>/nix/store/dpmvp969yhdqs7lm2r1a3gng7pyq6vy4-subversion-1.1.3/</filename>,
-while another version might be stored in
-<filename>/nix/store/5mq2jcn36ldlmh93yj1n8s9c95pj7c5s-subversion-1.1.2</filename>.
-The long strings prefixed to the directory names are cryptographic
-hashes<footnote><para>160-bit truncations of SHA-256 hashes encoded in
-a base-32 notation, to be precise.</para></footnote> of
-<emphasis>all</emphasis> inputs involved in building the package —
-sources, dependencies, compiler flags, and so on.  So if two
-packages differ in any way, they end up in different locations in
-the file system, so they don’t interfere with each other.  <xref
-linkend='fig-user-environments' /> shows a part of a typical Nix
-store.</para>
-
-<figure xml:id='fig-user-environments'><title>User environments</title>
-  <mediaobject>
-    <imageobject>
-      <imagedata fileref='figures/user-environments.png' format='PNG' />
-    </imageobject>
-  </mediaobject>
-</figure>
-
-<para>Of course, you wouldn’t want to type
-
-<screen>
-$ /nix/store/dpmvp969yhdq...-subversion-1.1.3/bin/svn</screen>
-
-every time you want to run Subversion.  Of course we could set up the
-<envar>PATH</envar> environment variable to include the
-<filename>bin</filename> directory of every package we want to use,
-but this is not very convenient since changing <envar>PATH</envar>
-doesn’t take effect for already existing processes.  The solution Nix
-uses is to create directory trees of symlinks to
-<emphasis>activated</emphasis> packages.  These are called
-<emphasis>user environments</emphasis> and they are packages
-themselves (though automatically generated by
-<command>nix-env</command>), so they too reside in the Nix store.  For
-instance, in <xref linkend='fig-user-environments' /> the user
-environment <filename>/nix/store/0c1p5z4kda11...-user-env</filename>
-contains a symlink to just Subversion 1.1.2 (arrows in the figure
-indicate symlinks).  This would be what we would obtain if we had done
-
-<screen>
-$ nix-env -i subversion</screen>
-
-on a set of Nix expressions that contained Subversion 1.1.2.</para>
-
-<para>This doesn’t in itself solve the problem, of course; you
-wouldn’t want to type
-<filename>/nix/store/0c1p5z4kda11...-user-env/bin/svn</filename>
-either.  That’s why there are symlinks outside of the store that point
-to the user environments in the store; for instance, the symlinks
-<filename>default-42-link</filename> and
-<filename>default-43-link</filename> in the example.  These are called
-<emphasis>generations</emphasis> since every time you perform a
-<command>nix-env</command> operation, a new user environment is
-generated based on the current one.  For instance, generation 43 was
-created from generation 42 when we did
-
-<screen>
-$ nix-env -i subversion mozilla</screen>
-
-on a set of Nix expressions that contained Mozilla and a new version
-of Subversion.</para>
-
-<para>Generations are grouped together into
-<emphasis>profiles</emphasis> so that different users don’t interfere
-with each other if they don’t want to.  For example:
-
-<screen>
-$ ls -l /nix/var/nix/profiles/
-...
-lrwxrwxrwx  1 eelco ... default-42-link -> /nix/store/0c1p5z4kda11...-user-env
-lrwxrwxrwx  1 eelco ... default-43-link -> /nix/store/3aw2pdyx2jfc...-user-env
-lrwxrwxrwx  1 eelco ... default -> default-43-link</screen>
-
-This shows a profile called <filename>default</filename>.  The file
-<filename>default</filename> itself is actually a symlink that points
-to the current generation.  When we do a <command>nix-env</command>
-operation, a new user environment and generation link are created
-based on the current one, and finally the <filename>default</filename>
-symlink is made to point at the new generation.  This last step is
-atomic on Unix, which explains how we can do atomic upgrades.  (Note
-that the building/installing of new packages doesn’t interfere in
-any way with old packages, since they are stored in different
-locations in the Nix store.)</para>
-
-<para>If you find that you want to undo a <command>nix-env</command>
-operation, you can just do
-
-<screen>
-$ nix-env --rollback</screen>
-
-which will just make the current generation link point at the previous
-link.  E.g., <filename>default</filename> would be made to point at
-<filename>default-42-link</filename>.  You can also switch to a
-specific generation:
-
-<screen>
-$ nix-env --switch-generation 43</screen>
-
-which in this example would roll forward to generation 43 again.  You
-can also see all available generations:
-
-<screen>
-$ nix-env --list-generations</screen></para>
-
-<para>Actually, there is another level of indirection not shown in the
-figure above.  You generally wouldn’t have
-<filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename>
-in your <envar>PATH</envar>.  Rather, there is a symlink
-<filename>~/.nix-profile</filename> that points to your current
-profile.  This means that you should put
-<filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar>
-(and indeed, that’s what the initialisation script
-<filename>/nix/etc/profile.d/nix.sh</filename> does).  This makes it
-easier to switch to a different profile.  You can do that using the
-command <command>nix-env --switch-profile</command>:
-
-<screen>
-$ nix-env --switch-profile /nix/var/nix/profiles/my-profile
-
-$ nix-env --switch-profile /nix/var/nix/profiles/default</screen>
-
-These commands switch to the <filename>my-profile</filename> and
-default profile, respectively.  If the profile doesn’t exist, it will
-be created automatically.  You should be careful about storing a
-profile in another location than the <filename>profiles</filename>
-directory, since otherwise it might not be used as a root of the
-garbage collector (see <xref linkend='sec-garbage-collection'
-/>).</para>
-
-<para>All <command>nix-env</command> operations work on the profile
-pointed to by <command>~/.nix-profile</command>, but you can override
-this using the <option>--profile</option> option (abbreviation
-<option>-p</option>):
-
-<screen>
-$ nix-env -p /nix/var/nix/profiles/other-profile -i subversion</screen>
-
-This will <emphasis>not</emphasis> change the
-<command>~/.nix-profile</command> symlink.</para>
-
-</section>
-
-
-<section xml:id='sec-garbage-collection'><title>Garbage collection</title>
-
-<para><command>nix-env</command> operations such as upgrades
-(<option>-u</option>) and uninstall (<option>-e</option>) never
-actually delete packages from the system.  All they do (as shown
-above) is to create a new user environment that no longer contains
-symlinks to the “deleted” packages.</para>
-
-<para>Of course, since disk space is not infinite, unused packages
-should be removed at some point.  You can do this by running the Nix
-garbage collector.  It will remove from the Nix store any package
-not used (directly or indirectly) by any generation of any
-profile.</para>
-
-<para>Note however that as long as old generations reference a
-package, it will not be deleted.  After all, we wouldn’t be able to
-do a rollback otherwise.  So in order for garbage collection to be
-effective, you should also delete (some) old generations.  Of course,
-this should only be done if you are certain that you will not need to
-roll back.</para>
-
-<para>To delete all old (non-current) generations of your current
-profile:
-
-<screen>
-$ nix-env --delete-generations old</screen>
-
-Instead of <literal>old</literal> you can also specify a list of
-generations, e.g.,
-
-<screen>
-$ nix-env --delete-generations 10 11 14</screen>
-
-</para>
-
-<para>After removing appropriate old generations you can run the
-garbage collector as follows:
-
-<screen>
-$ nix-store --gc</screen>
-
-If you are feeling uncertain, you can also first view what files would
-be deleted:
-
-<screen>
-$ nix-store --gc --print-dead</screen>
-
-Likewise, the option <option>--print-live</option> will show the paths
-that <emphasis>won’t</emphasis> be deleted.</para>
-
-<para>There is also a convenient little utility
-<command>nix-collect-garbage</command>, which when invoked with the
-<option>-d</option> (<option>--delete-old</option>) switch deletes all
-old generations of all profiles in
-<filename>/nix/var/nix/profiles</filename>.  So
-
-<screen>
-$ nix-collect-garbage -d</screen>
-
-is a quick and easy way to clean up your system.</para>
-
-
-
-
-<section xml:id="ssec-gc-roots"><title>Garbage collector roots</title>
-
-<para>The roots of the garbage collector are all store paths to which
-there are symlinks in the directory
-<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>.
-For instance, the following command makes the path
-<filename>/nix/store/d718ef...-foo</filename> a root of the collector:
-
-<screen>
-$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar</screen>
-	
-That is, after this command, the garbage collector will not remove
-<filename>/nix/store/d718ef...-foo</filename> or any of its
-dependencies.</para>
-
-<para>Subdirectories of
-<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>
-are also searched for symlinks.  Symlinks to non-store paths are
-followed and searched for roots, but symlinks to non-store paths
-<emphasis>inside</emphasis> the paths reached in that way are not
-followed to prevent infinite recursion.</para>
-
-</section>
-
-</section>
-
-
-<section xml:id="sec-channels"><title>Channels</title>
-
-<para>If you want to stay up to date with a set of packages, it’s not
-very convenient to manually download the latest set of Nix expressions
-for those packages, use <command>nix-pull</command> to register
-pre-built binaries (if available), and upgrade using
-<command>nix-env</command>.  Fortunately, there’s a better way:
-<emphasis>Nix channels</emphasis>.</para>
-
-<para>A Nix channel is just a URL that points to a place that contains
-a set of Nix expressions and a manifest.  Using the command <link
-linkend="sec-nix-channel"><command>nix-channel</command></link> you
-can automatically stay up to date with whatever is available at that
-URL.</para>
-
-<para>You can “subscribe” to a channel using
-<command>nix-channel --add</command>, e.g.,
-
-<screen>
-$ nix-channel --add http://nixos.org/channels/nixpkgs-unstable</screen>
-
-subscribes you to a channel that always contains that latest version
-of the Nix Packages collection.  (Instead of
-<literal>nixpkgs-unstable</literal> you could also subscribe to
-<literal>nixpkgs-stable</literal>, which should have a higher level of
-stability, but right now is just outdated.)  Subscribing really just
-means that the URL is added to the file
-<filename>~/.nix-channels</filename>.  Right now there is no command
-to “unsubscribe”; you should just edit that file manually
-and delete the offending URL.</para>
-
-<para>To obtain the latest Nix expressions available in a channel, do
-
-<screen>
-$ nix-channel --update</screen>
-
-This downloads the Nix expressions in every channel (downloaded from
-<literal><replaceable>url</replaceable>/nixexprs.tar.bz2</literal>)
-and registers any available pre-built binaries in every channel
-(by <command>nix-pull</command>ing
-<literal><replaceable>url</replaceable>/MANIFEST</literal>).  It also
-makes the union of each channel’s Nix expressions the default for
-<command>nix-env</command> operations.  Consequently, you can then say
-
-<screen>
-$ nix-env -u '*'</screen>
-
-to upgrade all packages in your profile to the latest versions
-available in the subscribed channels.</para>
-
-</section>
-
-
-<section xml:id="sec-one-click"><title>One-click installs</title>
-
-<para>Often, when you want to install a specific package (e.g., from
-the <link
-xlink:href="http://nixos.org/nixpkgs/">Nix
-Packages collection</link>), subscribing to a channel is a bit
-cumbersome.  And channels don’t help you at all if you want to install
-an older version of a package than the one provided by the current
-contents of the channel, or a package that has been removed from the
-channel.  That’s when <emphasis>one-click installs</emphasis> come in
-handy: you can just go to the web page that contains the package,
-click on it, and it will be installed with all the necessary
-dependencies.</para>
-
-<para>For instance, you can go to <link
-xlink:href="http://hydra.nixos.org/jobset/nixpkgs/trunk/channel/latest"
-/> and click on any link for the individual packages for your
-platform.  The first time you do this, your browser will ask what to
-do with <literal>application/nix-package</literal> files.  You should
-open them with <filename>/nix/bin/nix-install-package</filename>.
-This will open a window that asks you to confirm that you want to
-install the package.  When you answer <literal>Y</literal>, the
-package and all its dependencies will be installed.  This is a binary
-deployment mechanism — you get packages pre-compiled for the selected
-platform type.</para>
-
-<para>You can also install <literal>application/nix-package</literal>
-files from the command line directly.  See <xref
-linkend='sec-nix-install-package' /> for details.</para>
-
-</section>
-
-
-<section xml:id="sec-sharing-packages"><title>Sharing packages between machines</title>
-
-<para>Sometimes you want to copy a package from one machine to
-another.  Or, you want to install some packages and you know that
-another machine already has some or all of those packages or their
-dependencies.  In that case there are mechanisms to quickly copy
-packages between machines.</para>
-
-<para>The command <command
-linkend="sec-nix-copy-closure">nix-copy-closure</command> copies a Nix
-store path along with all its dependencies to or from another machine
-via the SSH protocol.  It doesn’t copy store paths that are already
-present on the target machine.  For example, the following command
-copies Firefox with all its dependencies:
-
-<screen>
-$ nix-copy-closure --to alice@itchy.example.org $(type -p firefox)</screen>
-
-See <xref linkend='sec-nix-copy-closure' /> for details.</para>
-
-<para>With <command linkend='refsec-nix-store-export'>nix-store
--export</command> and <command
-linkend='refsec-nix-store-import'>nix-store --import</command> you can
-write the closure of a store path (that is, the path and all its
-dependencies) to a file, and then unpack that file into another Nix
-store.  For example,
-
-<screen>
-$ nix-store --export $(nix-store -qR $(type -p firefox)) > firefox.closure</screen>
-
-writes the closure of Firefox to a file.  You can then copy this file
-to another machine and install the closure:
-
-<screen>
-$ nix-store --import &lt; firefox.closure</screen>
-
-Any store paths in the closure that are already present in the target
-store are ignored.  It is also possible to pipe the export into
-another command, e.g. to copy and install a closure directly to/on
-another machine:
-
-<screen>
-$ nix-store --export $(nix-store -qR $(type -p firefox)) | bzip2 | \
-    ssh alice@itchy.example.org "bunzip2 | nix-store --import"</screen>
-
-But note that <command>nix-copy-closure</command> is generally more
-efficient in this example because it only copies paths that are not
-already present in the target Nix store.</para>
-
-<para>Finally, if you can mount the Nix store of a remote machine in
-your local filesystem, Nix can copy paths from the remote Nix store to
-the local Nix store <emphasis>on demand</emphasis>.  For instance,
-suppose that you mount a remote machine containing a Nix store via
-<command
-xlink:href="http://fuse.sourceforge.net/sshfs.html">sshfs</command>:
-
-<screen>
-$ sshfs alice@itchy.example.org:/ /mnt</screen>
-
-You should then set the <envar>NIX_OTHER_STORES</envar> environment
-variable to tell Nix about this remote Nix store:
-
-<screen>
-$ export NIX_OTHER_STORES=/mnt/nix</screen>
-
-Then if you do any Nix operation, e.g.
-
-<screen>
-$ nix-env -i firefox</screen>
-
-and Nix has to build a path that it sees is already present in
-<filename>/mnt/nix</filename>, then it will just copy from there
-instead of building it from source.</para>
-
-
-</section>
-
-
-</chapter>
@@ -0,0 +1,194 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-basic-package-mgmt">
+
+<title>Basic Package Management</title>
+
+<para>The main command for package management is <link
+linkend="sec-nix-env"><command>nix-env</command></link>.  You can use
+it to install, upgrade, and erase packages, and to query what
+packages are installed or are available for installation.</para>
+
+<para>In Nix, different users can have different “views”
+on the set of installed applications.  That is, there might be lots of
+applications present on the system (possibly in many different
+versions), but users can have a specific selection of those active —
+where “active” just means that it appears in a directory
+in the user’s <envar>PATH</envar>.  Such a view on the set of
+installed applications is called a <emphasis>user
+environment</emphasis>, which is just a directory tree consisting of
+symlinks to the files of the active applications.  </para>
+
+<para>Components are installed from a set of <emphasis>Nix
+expressions</emphasis> that tell Nix how to build those packages,
+including, if necessary, their dependencies.  There is a collection of
+Nix expressions called the Nix Package collection that contains
+packages ranging from basic development stuff such as GCC and Glibc,
+to end-user applications like Mozilla Firefox.  (Nix is however not
+tied to the Nix Package collection; you could write your own Nix
+expressions based on it, or completely new ones.)</para>
+
+<para>You can manually download the latest version of Nixpkgs from
+<link xlink:href='http://nixos.org/nixpkgs/download.html'/>. However,
+it’s much more convenient to use the Nixpkgs
+<emphasis>channel</emphasis>, since it makes it easy to stay up to
+date with new versions of Nixpkgs. (Channels are described in more
+detail in <xref linkend="sec-channels"/>.) Nixpkgs is automatically
+added to your list of “subscribed” channels when you install
+Nix. If this is not the case for some reason, you can add it as
+follows:
+
+<screen>
+$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable
+$ nix-channel --update
+</screen>
+
+</para>
+
+<note><para>On NixOS, you’re automatically subscribed to a NixOS
+channel corresponding to your NixOS major release
+(e.g. <uri>http://nixos.org/channels/nixos-14.12</uri>). A NixOS
+channel is identical to the Nixpkgs channel, except that it contains
+only Linux binaries and is updated only if a set of regression tests
+succeed.</para></note>
+
+<para>You can view the set of available packages in Nixpkgs:
+
+<screen>
+$ nix-env -qa
+aterm-2.2
+bash-3.0
+binutils-2.15
+bison-1.875d
+blackdown-1.4.2
+bzip2-1.0.2
+…</screen>
+
+The flag <option>-q</option> specifies a query operation, and
+<option>-a</option> means that you want to show the “available” (i.e.,
+installable) packages, as opposed to the installed packages. If you
+downloaded Nixpkgs yourself, or if you checked it out from GitHub,
+then you need to pass the path to your Nixpkgs tree using the
+<option>-f</option> flag:
+
+<screen>
+$ nix-env -qaf <replaceable>/path/to/nixpkgs</replaceable>
+</screen>
+
+where <replaceable>/path/to/nixpkgs</replaceable> is where you’ve
+unpacked or checked out Nixpkgs.</para>
+
+<para>You can select specific packages by name:
+
+<screen>
+$ nix-env -qa firefox
+firefox-34.0.5
+firefox-with-plugins-34.0.5
+</screen>
+
+and using regular expressions:
+
+<screen>
+$ nix-env -qa 'firefox.*'
+</screen>
+
+</para>
+
+<para>It is also possible to see the <emphasis>status</emphasis> of
+available packages, i.e., whether they are installed into the user
+environment and/or present in the system:
+
+<screen>
+$ nix-env -qas
+…
+-PS bash-3.0
+--S binutils-2.15
+IPS bison-1.875d
+…</screen>
+
+The first character (<literal>I</literal>) indicates whether the
+package is installed in your current user environment.  The second
+(<literal>P</literal>) indicates whether it is present on your system
+(in which case installing it into your user environment would be a
+very quick operation).  The last one (<literal>S</literal>) indicates
+whether there is a so-called <emphasis>substitute</emphasis> for the
+package, which is Nix’s mechanism for doing binary deployment.  It
+just means that Nix knows that it can fetch a pre-built package from
+somewhere (typically a network server) instead of building it
+locally.</para>
+
+<para>You can install a package using <literal>nix-env -i</literal>.
+For instance,
+
+<screen>
+$ nix-env -i subversion</screen>
+
+will install the package called <literal>subversion</literal> (which
+is, of course, the <link
+xlink:href='http://subversion.tigris.org/'>Subversion version
+management system</link>).</para>
+
+<note><para>When you ask Nix to install a package, it will first try
+to get it in pre-compiled form from a <emphasis>binary
+cache</emphasis>. By default, Nix will use the binary cache
+<uri>https://cache.nixos.org</uri>; it contains binaries for most
+packages in Nixpkgs. Only if no binary is available in the binary
+cache, Nix will build the package from source. So if <literal>nix-env
+-i subversion</literal> results in Nix building stuff from source,
+then either the package is not built for your platform by the Nixpkgs
+build servers, or your version of Nixpkgs is too old or too new. For
+instance, if you have a very recent checkout of Nixpkgs, then the
+Nixpkgs build servers may not have had a chance to build everything
+and upload the resulting binaries to
+<uri>https://cache.nixos.org</uri>. The Nixpkgs channel is only
+updated after all binaries have been uploaded to the cache, so if you
+stick to the Nixpkgs channel (rather than using a Git checkout of the
+Nixpkgs tree), you will get binaries for most packages.</para></note>
+
+<para>Naturally, packages can also be uninstalled:
+
+<screen>
+$ nix-env -e subversion</screen>
+
+</para>
+
+<para>Upgrading to a new version is just as easy.  If you have a new
+release of Nix Packages, you can do:
+
+<screen>
+$ nix-env -u subversion</screen>
+
+This will <emphasis>only</emphasis> upgrade Subversion if there is a
+“newer” version in the new set of Nix expressions, as
+defined by some pretty arbitrary rules regarding ordering of version
+numbers (which generally do what you’d expect of them).  To just
+unconditionally replace Subversion with whatever version is in the Nix
+expressions, use <parameter>-i</parameter> instead of
+<parameter>-u</parameter>; <parameter>-i</parameter> will remove
+whatever version is already installed.</para>
+
+<para>You can also upgrade all packages for which there are newer
+versions:
+
+<screen>
+$ nix-env -u</screen>
+
+</para>
+
+<para>Sometimes it’s useful to be able to ask what
+<command>nix-env</command> would do, without actually doing it.  For
+instance, to find out what packages would be upgraded by
+<literal>nix-env -u</literal>, you can do
+
+<screen>
+$ nix-env -u --dry-run
+(dry run; not doing anything)
+upgrading `libxslt-1.1.0' to `libxslt-1.1.10'
+upgrading `graphviz-1.10' to `graphviz-1.12'
+upgrading `coreutils-5.0' to `coreutils-5.2.1'</screen>
+
+</para>
+
+</chapter>
@@ -0,0 +1,70 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="ssec-binary-cache-substituter">
+
+<title>Serving a Nix store via HTTP</title>
+
+<para>You can easily share the Nix store of a machine via HTTP. This
+allows other machines to fetch store paths from that machine to speed
+up installations. It uses the same <emphasis>binary cache</emphasis>
+mechanism that Nix usually uses to fetch pre-built binaries from
+<uri>https://cache.nixos.org</uri>.</para>
+
+<para>The daemon that handles binary cache requests via HTTP,
+<command>nix-serve</command>, is not part of the Nix distribution, but
+you can install it from Nixpkgs:
+
+<screen>
+$ nix-env -i nix-serve
+</screen>
+
+You can then start the server, listening for HTTP connections on
+whatever port you like:
+
+<screen>
+$ nix-serve -p 8080
+</screen>
+
+To check whether it works, try the following on the client:
+
+<screen>
+$ curl http://avalon:8080/nix-cache-info
+</screen>
+
+which should print something like:
+
+<screen>
+StoreDir: /nix/store
+WantMassQuery: 1
+Priority: 30
+</screen>
+
+</para>
+
+<para>On the client side, you can tell Nix to use your binary cache
+using <option>--option extra-binary-caches</option>, e.g.:
+
+<screen>
+$ nix-env -i firefox --option extra-binary-caches http://avalon:8080/
+</screen>
+
+The option <option>extra-binary-caches</option> tells Nix to use this
+binary cache in addition to your default caches, such as
+<uri>https://cache.nixos.org</uri>. Thus, for any path in the closure
+of Firefox, Nix will first check if the path is available on the
+server <literal>avalon</literal> or another binary caches. If not, it
+will fall back to building from source.</para>
+
+<para>You can also tell Nix to always use your binary cache by adding
+a line to the <filename linkend="sec-conf-file">nix.conf</filename>
+configuration file like this:
+
+<programlisting>
+binary-caches = http://avalon:8080/ https://cache.nixos.org/
+</programlisting>
+
+</para>
+
+</section>
@@ -0,0 +1,57 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-channels">
+
+<title>Channels</title>
+
+<para>If you want to stay up to date with a set of packages, it’s not
+very convenient to manually download the latest set of Nix expressions
+for those packages and upgrade using <command>nix-env</command>.
+Fortunately, there’s a better way: <emphasis>Nix
+channels</emphasis>.</para>
+
+<para>A Nix channel is just a URL that points to a place that contains
+a set of Nix expressions and a manifest.  Using the command <link
+linkend="sec-nix-channel"><command>nix-channel</command></link> you
+can automatically stay up to date with whatever is available at that
+URL.</para>
+
+<para>You can “subscribe” to a channel using
+<command>nix-channel --add</command>, e.g.,
+
+<screen>
+$ nix-channel --add https://nixos.org/channels/nixpkgs-unstable</screen>
+
+subscribes you to a channel that always contains that latest version
+of the Nix Packages collection.  (Subscribing really just means that
+the URL is added to the file <filename>~/.nix-channels</filename>,
+where it is read by subsequent calls to <command>nix-channel
+--update</command>.) You can “unsubscribe” using <command>nix-channel
+--remove</command>:
+
+<screen>
+$ nix-channel --remove nixpkgs
+</screen>
+</para>
+
+<para>To obtain the latest Nix expressions available in a channel, do
+
+<screen>
+$ nix-channel --update</screen>
+
+This downloads and unpacks the Nix expressions in every channel
+(downloaded from <literal><replaceable>url</replaceable>/nixexprs.tar.bz2</literal>).
+It also makes the union of each channel’s Nix expressions available by
+default to <command>nix-env</command> operations (via the symlink
+<filename>~/.nix-defexpr/channels</filename>).  Consequently, you can
+then say
+
+<screen>
+$ nix-env -u</screen>
+
+to upgrade all packages in your profile to the latest versions
+available in the subscribed channels.</para>
+
+</chapter>
@@ -0,0 +1,50 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="ssec-copy-closure">
+
+<title>Copying Closures Via SSH</title>
+
+<para>The command <command
+linkend="sec-nix-copy-closure">nix-copy-closure</command> copies a Nix
+store path along with all its dependencies to or from another machine
+via the SSH protocol.  It doesn’t copy store paths that are already
+present on the target machine.  For example, the following command
+copies Firefox with all its dependencies:
+
+<screen>
+$ nix-copy-closure --to alice@itchy.example.org $(type -p firefox)</screen>
+
+See <xref linkend='sec-nix-copy-closure' /> for details.</para>
+
+<para>With <command linkend='refsec-nix-store-export'>nix-store
+--export</command> and <command
+linkend='refsec-nix-store-import'>nix-store --import</command> you can
+write the closure of a store path (that is, the path and all its
+dependencies) to a file, and then unpack that file into another Nix
+store.  For example,
+
+<screen>
+$ nix-store --export $(nix-store -qR $(type -p firefox)) > firefox.closure</screen>
+
+writes the closure of Firefox to a file.  You can then copy this file
+to another machine and install the closure:
+
+<screen>
+$ nix-store --import &lt; firefox.closure</screen>
+
+Any store paths in the closure that are already present in the target
+store are ignored.  It is also possible to pipe the export into
+another command, e.g. to copy and install a closure directly to/on
+another machine:
+
+<screen>
+$ nix-store --export $(nix-store -qR $(type -p firefox)) | bzip2 | \
+    ssh alice@itchy.example.org "bunzip2 | nix-store --import"</screen>
+
+However, <command>nix-copy-closure</command> is generally more
+efficient because it only copies paths that are not already present in
+the target Nix store.</para>
+
+</section>
@@ -0,0 +1,77 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='sec-garbage-collection'>
+
+<title>Garbage Collection</title>
+
+<para><command>nix-env</command> operations such as upgrades
+(<option>-u</option>) and uninstall (<option>-e</option>) never
+actually delete packages from the system.  All they do (as shown
+above) is to create a new user environment that no longer contains
+symlinks to the “deleted” packages.</para>
+
+<para>Of course, since disk space is not infinite, unused packages
+should be removed at some point.  You can do this by running the Nix
+garbage collector.  It will remove from the Nix store any package
+not used (directly or indirectly) by any generation of any
+profile.</para>
+
+<para>Note however that as long as old generations reference a
+package, it will not be deleted.  After all, we wouldn’t be able to
+do a rollback otherwise.  So in order for garbage collection to be
+effective, you should also delete (some) old generations.  Of course,
+this should only be done if you are certain that you will not need to
+roll back.</para>
+
+<para>To delete all old (non-current) generations of your current
+profile:
+
+<screen>
+$ nix-env --delete-generations old</screen>
+
+Instead of <literal>old</literal> you can also specify a list of
+generations, e.g.,
+
+<screen>
+$ nix-env --delete-generations 10 11 14</screen>
+
+To delete all generations older than a specified number of days
+(except the current generation), use the <literal>d</literal>
+suffix. For example,
+
+<screen>
+$ nix-env --delete-generations 14d</screen>
+
+deletes all generations older than two weeks.</para>
+
+<para>After removing appropriate old generations you can run the
+garbage collector as follows:
+
+<screen>
+$ nix-store --gc</screen>
+
+If you are feeling uncertain, you can also first view what files would
+be deleted:
+
+<screen>
+$ nix-store --gc --print-dead</screen>
+
+Likewise, the option <option>--print-live</option> will show the paths
+that <emphasis>won’t</emphasis> be deleted.</para>
+
+<para>There is also a convenient little utility
+<command>nix-collect-garbage</command>, which when invoked with the
+<option>-d</option> (<option>--delete-old</option>) switch deletes all
+old generations of all profiles in
+<filename>/nix/var/nix/profiles</filename>.  So
+
+<screen>
+$ nix-collect-garbage -d</screen>
+
+is a quick and easy way to clean up your system.</para>
+
+<xi:include href="garbage-collector-roots.xml" />
+
+</chapter>
@@ -0,0 +1,29 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-gc-roots">
+
+<title>Garbage Collector Roots</title>
+
+<para>The roots of the garbage collector are all store paths to which
+there are symlinks in the directory
+<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>.
+For instance, the following command makes the path
+<filename>/nix/store/d718ef...-foo</filename> a root of the collector:
+
+<screen>
+$ ln -s /nix/store/d718ef...-foo /nix/var/nix/gcroots/bar</screen>
+	
+That is, after this command, the garbage collector will not remove
+<filename>/nix/store/d718ef...-foo</filename> or any of its
+dependencies.</para>
+
+<para>Subdirectories of
+<filename><replaceable>prefix</replaceable>/nix/var/nix/gcroots</filename>
+are also searched for symlinks.  Symlinks to non-store paths are
+followed and searched for roots, but symlinks to non-store paths
+<emphasis>inside</emphasis> the paths reached in that way are not
+followed to prevent infinite recursion.</para>
+
+</section>
@@ -0,0 +1,23 @@
+<part xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id='chap-package-management'>
+
+<title>Package Management</title>
+
+<partintro>
+<para>This chapter discusses how to do package management with Nix,
+i.e., how to obtain, install, upgrade, and erase packages.  This is
+the “user’s” perspective of the Nix system — people
+who want to <emphasis>create</emphasis> packages should consult
+<xref linkend='chap-writing-nix-expressions' />.</para>
+</partintro>
+
+<xi:include href="basic-package-mgmt.xml" />
+<xi:include href="profiles.xml" />
+<xi:include href="garbage-collection.xml" />
+<xi:include href="channels.xml" />
+<xi:include href="sharing-packages.xml" />
+
+</part>
@@ -0,0 +1,158 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-profiles">
+
+<title>Profiles</title>
+
+<para>Profiles and user environments are Nix’s mechanism for
+implementing the ability to allow different users to have different
+configurations, and to do atomic upgrades and rollbacks.  To
+understand how they work, it’s useful to know a bit about how Nix
+works.  In Nix, packages are stored in unique locations in the
+<emphasis>Nix store</emphasis> (typically,
+<filename>/nix/store</filename>).  For instance, a particular version
+of the Subversion package might be stored in a directory
+<filename>/nix/store/dpmvp969yhdqs7lm2r1a3gng7pyq6vy4-subversion-1.1.3/</filename>,
+while another version might be stored in
+<filename>/nix/store/5mq2jcn36ldlmh93yj1n8s9c95pj7c5s-subversion-1.1.2</filename>.
+The long strings prefixed to the directory names are cryptographic
+hashes<footnote><para>160-bit truncations of SHA-256 hashes encoded in
+a base-32 notation, to be precise.</para></footnote> of
+<emphasis>all</emphasis> inputs involved in building the package —
+sources, dependencies, compiler flags, and so on.  So if two
+packages differ in any way, they end up in different locations in
+the file system, so they don’t interfere with each other.  <xref
+linkend='fig-user-environments' /> shows a part of a typical Nix
+store.</para>
+
+<figure xml:id='fig-user-environments'><title>User environments</title>
+  <mediaobject>
+    <imageobject>
+      <imagedata fileref='../figures/user-environments.png' format='PNG' />
+    </imageobject>
+  </mediaobject>
+</figure>
+
+<para>Of course, you wouldn’t want to type
+
+<screen>
+$ /nix/store/dpmvp969yhdq...-subversion-1.1.3/bin/svn</screen>
+
+every time you want to run Subversion.  Of course we could set up the
+<envar>PATH</envar> environment variable to include the
+<filename>bin</filename> directory of every package we want to use,
+but this is not very convenient since changing <envar>PATH</envar>
+doesn’t take effect for already existing processes.  The solution Nix
+uses is to create directory trees of symlinks to
+<emphasis>activated</emphasis> packages.  These are called
+<emphasis>user environments</emphasis> and they are packages
+themselves (though automatically generated by
+<command>nix-env</command>), so they too reside in the Nix store.  For
+instance, in <xref linkend='fig-user-environments' /> the user
+environment <filename>/nix/store/0c1p5z4kda11...-user-env</filename>
+contains a symlink to just Subversion 1.1.2 (arrows in the figure
+indicate symlinks).  This would be what we would obtain if we had done
+
+<screen>
+$ nix-env -i subversion</screen>
+
+on a set of Nix expressions that contained Subversion 1.1.2.</para>
+
+<para>This doesn’t in itself solve the problem, of course; you
+wouldn’t want to type
+<filename>/nix/store/0c1p5z4kda11...-user-env/bin/svn</filename>
+either.  That’s why there are symlinks outside of the store that point
+to the user environments in the store; for instance, the symlinks
+<filename>default-42-link</filename> and
+<filename>default-43-link</filename> in the example.  These are called
+<emphasis>generations</emphasis> since every time you perform a
+<command>nix-env</command> operation, a new user environment is
+generated based on the current one.  For instance, generation 43 was
+created from generation 42 when we did
+
+<screen>
+$ nix-env -i subversion firefox</screen>
+
+on a set of Nix expressions that contained Firefox and a new version
+of Subversion.</para>
+
+<para>Generations are grouped together into
+<emphasis>profiles</emphasis> so that different users don’t interfere
+with each other if they don’t want to.  For example:
+
+<screen>
+$ ls -l /nix/var/nix/profiles/
+...
+lrwxrwxrwx  1 eelco ... default-42-link -> /nix/store/0c1p5z4kda11...-user-env
+lrwxrwxrwx  1 eelco ... default-43-link -> /nix/store/3aw2pdyx2jfc...-user-env
+lrwxrwxrwx  1 eelco ... default -> default-43-link</screen>
+
+This shows a profile called <filename>default</filename>.  The file
+<filename>default</filename> itself is actually a symlink that points
+to the current generation.  When we do a <command>nix-env</command>
+operation, a new user environment and generation link are created
+based on the current one, and finally the <filename>default</filename>
+symlink is made to point at the new generation.  This last step is
+atomic on Unix, which explains how we can do atomic upgrades.  (Note
+that the building/installing of new packages doesn’t interfere in
+any way with old packages, since they are stored in different
+locations in the Nix store.)</para>
+
+<para>If you find that you want to undo a <command>nix-env</command>
+operation, you can just do
+
+<screen>
+$ nix-env --rollback</screen>
+
+which will just make the current generation link point at the previous
+link.  E.g., <filename>default</filename> would be made to point at
+<filename>default-42-link</filename>.  You can also switch to a
+specific generation:
+
+<screen>
+$ nix-env --switch-generation 43</screen>
+
+which in this example would roll forward to generation 43 again.  You
+can also see all available generations:
+
+<screen>
+$ nix-env --list-generations</screen></para>
+
+<para>You generally wouldn’t have
+<filename>/nix/var/nix/profiles/<replaceable>some-profile</replaceable>/bin</filename>
+in your <envar>PATH</envar>.  Rather, there is a symlink
+<filename>~/.nix-profile</filename> that points to your current
+profile.  This means that you should put
+<filename>~/.nix-profile/bin</filename> in your <envar>PATH</envar>
+(and indeed, that’s what the initialisation script
+<filename>/nix/etc/profile.d/nix.sh</filename> does).  This makes it
+easier to switch to a different profile.  You can do that using the
+command <command>nix-env --switch-profile</command>:
+
+<screen>
+$ nix-env --switch-profile /nix/var/nix/profiles/my-profile
+
+$ nix-env --switch-profile /nix/var/nix/profiles/default</screen>
+
+These commands switch to the <filename>my-profile</filename> and
+default profile, respectively.  If the profile doesn’t exist, it will
+be created automatically.  You should be careful about storing a
+profile in another location than the <filename>profiles</filename>
+directory, since otherwise it might not be used as a root of the
+garbage collector (see <xref linkend='sec-garbage-collection'
+/>).</para>
+
+<para>All <command>nix-env</command> operations work on the profile
+pointed to by <command>~/.nix-profile</command>, but you can override
+this using the <option>--profile</option> option (abbreviation
+<option>-p</option>):
+
+<screen>
+$ nix-env -p /nix/var/nix/profiles/other-profile -i subversion</screen>
+
+This will <emphasis>not</emphasis> change the
+<command>~/.nix-profile</command> symlink.</para>
+
+</chapter>
@@ -0,0 +1,19 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-sharing-packages">
+
+<title>Sharing Packages Between Machines</title>
+
+<para>Sometimes you want to copy a package from one machine to
+another.  Or, you want to install some packages and you know that
+another machine already has some or all of those packages or their
+dependencies.  In that case there are mechanisms to quickly copy
+packages between machines.</para>
+
+<xi:include href="binary-cache-substituter.xml" />
+<xi:include href="copy-closure.xml" />
+<xi:include href="ssh-substituter.xml" />
+
+</chapter>
@@ -0,0 +1,73 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="ssec-ssh-substituter">
+
+<title>Serving a Nix store via SSH</title>
+
+<para>You can tell Nix to automatically fetch needed binaries from a
+remote Nix store via SSH. For example, the following installs Firefox,
+automatically fetching any store paths in Firefox’s closure if they
+are available on the server <literal>avalon</literal>:
+
+<screen>
+$ nix-env -i firefox --option ssh-substituter-hosts alice@avalon
+</screen>
+
+This works similar to the binary cache substituter that Nix usually
+uses, only using SSH instead of HTTP: if a store path
+<literal>P</literal> is needed, Nix will first check if it’s available
+in the Nix store on <literal>avalon</literal>. If not, it will fall
+back to using the binary cache substituter, and then to building from
+source.</para>
+
+<note><para>The SSH substituter currently does not allow you to enter
+an SSH passphrase interactively. Therefore, you should use
+<command>ssh-add</command> to load the decrypted private key into
+<command>ssh-agent</command>.</para></note>
+
+<para>You can also copy the closure of some store path, without
+installing it into your profile, e.g.
+
+<screen>
+$ nix-store -r /nix/store/m85bxg…-firefox-34.0.5 --option ssh-substituter-hosts alice@avalon
+</screen>
+
+This is essentially equivalent to doing
+
+<screen>
+$ nix-copy-closure --from alice@avalon /nix/store/m85bxg…-firefox-34.0.5
+</screen>
+
+</para>
+
+<para>You can use SSH’s <emphasis>forced command</emphasis> feature to
+set up a restricted user account for SSH substituter access, allowing
+read-only access to the local Nix store, but nothing more. For
+example, add the following lines to <filename>sshd_config</filename>
+to restrict the user <literal>nix-ssh</literal>:
+
+<programlisting>
+Match User nix-ssh
+  AllowAgentForwarding no
+  AllowTcpForwarding no
+  PermitTTY no
+  PermitTunnel no
+  X11Forwarding no
+  ForceCommand nix-store --serve
+Match All
+</programlisting>
+
+On NixOS, you can accomplish the same by adding the following to your
+<filename>configuration.nix</filename>:
+
+<programlisting>
+nix.sshServe.enable = true;
+nix.sshServe.keys = [ "ssh-dss AAAAB3NzaC1k... bob@example.org" ];
+</programlisting>
+
+where the latter line lists the public keys of users that are allowed
+to connect.</para>
+
+</section>
@@ -0,0 +1,47 @@
+<appendix xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="sec-relnotes">
+
+<title>Nix Release Notes</title>
+
+<!--
+<partintro>
+<para>This section lists the release notes for each stable version of Nix.</para>
+</partintro>
+-->
+
+<xi:include href="rl-1.12.xml" />
+<xi:include href="rl-1.11.xml" />
+<xi:include href="rl-1.10.xml" />
+<xi:include href="rl-1.9.xml" />
+<xi:include href="rl-1.8.xml" />
+<xi:include href="rl-1.7.xml" />
+<xi:include href="rl-1.6.1.xml" />
+<xi:include href="rl-1.6.xml" />
+<xi:include href="rl-1.5.2.xml" />
+<xi:include href="rl-1.5.xml" />
+<xi:include href="rl-1.4.xml" />
+<xi:include href="rl-1.3.xml" />
+<xi:include href="rl-1.2.xml" />
+<xi:include href="rl-1.1.xml" />
+<xi:include href="rl-1.0.xml" />
+<xi:include href="rl-0.16.xml" />
+<xi:include href="rl-0.15.xml" />
+<xi:include href="rl-0.14.xml" />
+<xi:include href="rl-0.13.xml" />
+<xi:include href="rl-0.12.xml" />
+<xi:include href="rl-0.11.xml" />
+<xi:include href="rl-0.10.1.xml" />
+<xi:include href="rl-0.10.xml" />
+<xi:include href="rl-0.9.2.xml" />
+<xi:include href="rl-0.9.1.xml" />
+<xi:include href="rl-0.9.xml" />
+<xi:include href="rl-0.8.1.xml" />
+<xi:include href="rl-0.8.xml" />
+<xi:include href="rl-0.7.xml" />
+<xi:include href="rl-0.6.xml" />
+<xi:include href="rl-0.5.xml" />
+
+</appendix>
@@ -0,0 +1,13 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-relnotes-0.10.1">
+
+<title>Release 0.10.1 (2006-10-11)</title>
+
+<para>This release fixes two somewhat obscure bugs that occur when
+evaluating Nix expressions that are stored inside the Nix store
+(<literal>NIX-67</literal>).  These do not affect most users.</para>
+
+</section>
@@ -0,0 +1,323 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ch-relnotes-0.10">
+
+<title>Release 0.10 (2006-10-06)</title>
+
+<note><para>This version of Nix uses Berkeley DB 4.4 instead of 4.3.
+The database is upgraded automatically, but you should be careful not
+to use old versions of Nix that still use Berkeley DB 4.3.  In
+particular, if you use a Nix installed through Nix, you should run
+
+<screen>
+$ nix-store --clear-substitutes</screen>
+
+first.</para></note>
+
+<warning><para>Also, the database schema has changed slighted to fix a
+performance issue (see below).  When you run any Nix 0.10 command for
+the first time, the database will be upgraded automatically.  This is
+irreversible.</para></warning>
+
+<itemizedlist>
+
+
+  <!-- Usability / features -->
+
+
+  <listitem><para><command>nix-env</command> usability improvements:
+
+    <itemizedlist>
+
+      <listitem><para>An option <option>--compare-versions</option>
+      (or <option>-c</option>) has been added to <command>nix-env
+      --query</command> to allow you to compare installed versions of
+      packages to available versions, or vice versa.  An easy way to
+      see if you are up to date with what’s in your subscribed
+      channels is <literal>nix-env -qc \*</literal>.</para></listitem>
+
+      <listitem><para><literal>nix-env --query</literal> now takes as
+      arguments a list of package names about which to show
+      information, just like <option>--install</option>, etc.: for
+      example, <literal>nix-env -q gcc</literal>.  Note that to show
+      all derivations, you need to specify
+      <literal>\*</literal>.</para></listitem>
+
+      <listitem><para><literal>nix-env -i
+      <replaceable>pkgname</replaceable></literal> will now install
+      the highest available version of
+      <replaceable>pkgname</replaceable>, rather than installing all
+      available versions (which would probably give collisions)
+      (<literal>NIX-31</literal>).</para></listitem>
+
+      <listitem><para><literal>nix-env (-i|-u) --dry-run</literal> now
+      shows exactly which missing paths will be built or
+      substituted.</para></listitem>
+
+      <listitem><para><literal>nix-env -qa --description</literal>
+      shows human-readable descriptions of packages, provided that
+      they have a <literal>meta.description</literal> attribute (which
+      most packages in Nixpkgs don’t have yet).</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para>New language features:
+
+    <itemizedlist>
+
+      <listitem><para>Reference scanning (which happens after each
+      build) is much faster and takes a constant amount of
+      memory.</para></listitem>
+
+      <listitem><para>String interpolation.  Expressions like
+
+<programlisting>
+"--with-freetype2-library=" + freetype + "/lib"</programlisting>
+
+      can now be written as
+
+<programlisting>
+"--with-freetype2-library=${freetype}/lib"</programlisting>
+
+      You can write arbitrary expressions within
+      <literal>${<replaceable>...</replaceable>}</literal>, not just
+      identifiers.</para></listitem>
+
+      <listitem><para>Multi-line string literals.</para></listitem>
+
+      <listitem><para>String concatenations can now involve
+      derivations, as in the example <code>"--with-freetype2-library="
+      + freetype + "/lib"</code>.  This was not previously possible
+      because we need to register that a derivation that uses such a
+      string is dependent on <literal>freetype</literal>.  The
+      evaluator now properly propagates this information.
+      Consequently, the subpath operator (<literal>~</literal>) has
+      been deprecated.</para></listitem>
+
+      <listitem><para>Default values of function arguments can now
+      refer to other function arguments; that is, all arguments are in
+      scope in the default values
+      (<literal>NIX-45</literal>).</para></listitem>
+
+      <!--
+      <listitem><para>TODO: domain checks (r5895).</para></listitem>
+      -->
+
+      <listitem><para>Lots of new built-in primitives, such as
+      functions for list manipulation and integer arithmetic.  See the
+      manual for a complete list.  All primops are now available in
+      the set <varname>builtins</varname>, allowing one to test for
+      the availability of primop in a backwards-compatible
+      way.</para></listitem>
+
+      <listitem><para>Real let-expressions: <literal>let x = ...;
+      ... z = ...; in ...</literal>.</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para>New commands <command>nix-pack-closure</command> and
+  <command>nix-unpack-closure</command> than can be used to easily
+  transfer a store path with all its dependencies to another machine.
+  Very convenient whenever you have some package on your machine and
+  you want to copy it somewhere else.</para></listitem>
+
+
+  <listitem><para>XML support:
+
+    <itemizedlist>
+
+      <listitem><para><literal>nix-env -q --xml</literal> prints the
+      installed or available packages in an XML representation for
+      easy processing by other tools.</para></listitem>
+
+      <listitem><para><literal>nix-instantiate --eval-only
+      --xml</literal> prints an XML representation of the resulting
+      term.  (The new flag <option>--strict</option> forces ‘deep’
+      evaluation of the result, i.e., list elements and attributes are
+      evaluated recursively.)</para></listitem>
+
+      <listitem><para>In Nix expressions, the primop
+      <function>builtins.toXML</function> converts a term to an XML
+      representation.  This is primarily useful for passing structured
+      information to builders.</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para>You can now unambiguously specify which derivation to
+  build or install in <command>nix-env</command>,
+  <command>nix-instantiate</command> and <command>nix-build</command>
+  using the <option>--attr</option> / <option>-A</option> flags, which
+  takes an attribute name as argument.  (Unlike symbolic package names
+  such as <literal>subversion-1.4.0</literal>, attribute names in an
+  attribute set are unique.)  For instance, a quick way to perform a
+  test build of a package in Nixpkgs is <literal>nix-build
+  pkgs/top-level/all-packages.nix -A
+  <replaceable>foo</replaceable></literal>.  <literal>nix-env -q
+  --attr</literal> shows the attribute names corresponding to each
+  derivation.</para></listitem>
+
+
+  <listitem><para>If the top-level Nix expression used by
+  <command>nix-env</command>, <command>nix-instantiate</command> or
+  <command>nix-build</command> evaluates to a function whose arguments
+  all have default values, the function will be called automatically.
+  Also, the new command-line switch <option>--arg
+  <replaceable>name</replaceable>
+  <replaceable>value</replaceable></option> can be used to specify
+  function arguments on the command line.</para></listitem>
+
+
+  <listitem><para><literal>nix-install-package --url
+  <replaceable>URL</replaceable></literal> allows a package to be
+  installed directly from the given URL.</para></listitem>
+
+
+  <listitem><para>Nix now works behind an HTTP proxy server; just set
+  the standard environment variables <envar>http_proxy</envar>,
+  <envar>https_proxy</envar>, <envar>ftp_proxy</envar> or
+  <envar>all_proxy</envar> appropriately.  Functions such as
+  <function>fetchurl</function> in Nixpkgs also respect these
+  variables.</para></listitem>
+
+
+  <listitem><para><literal>nix-build -o
+  <replaceable>symlink</replaceable></literal> allows the symlink to
+  the build result to be named something other than
+  <literal>result</literal>.</para></listitem>
+
+
+  <!-- Stability / performance / etc. -->
+
+
+  <listitem><para>Platform support:
+
+    <itemizedlist>
+
+      <listitem><para>Support for 64-bit platforms, provided a <link
+      xlink:href="http://bugzilla.sen.cwi.nl:8080/show_bug.cgi?id=606">suitably
+      patched ATerm library</link> is used.  Also, files larger than 2
+      GiB are now supported.</para></listitem>
+
+      <listitem><para>Added support for Cygwin (Windows,
+      <literal>i686-cygwin</literal>), Mac OS X on Intel
+      (<literal>i686-darwin</literal>) and Linux on PowerPC
+      (<literal>powerpc-linux</literal>).</para></listitem>
+
+      <listitem><para>Users of SMP and multicore machines will
+      appreciate that the number of builds to be performed in parallel
+      can now be specified in the configuration file in the
+      <literal>build-max-jobs</literal> setting.</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para>Garbage collector improvements:
+
+    <itemizedlist>
+
+      <listitem><para>Open files (such as running programs) are now
+      used as roots of the garbage collector.  This prevents programs
+      that have been uninstalled from being garbage collected while
+      they are still running.  The script that detects these
+      additional runtime roots
+      (<filename>find-runtime-roots.pl</filename>) is inherently
+      system-specific, but it should work on Linux and on all
+      platforms that have the <command>lsof</command>
+      utility.</para></listitem>
+
+      <listitem><para><literal>nix-store --gc</literal>
+      (a.k.a. <command>nix-collect-garbage</command>) prints out the
+      number of bytes freed on standard output.  <literal>nix-store
+      --gc --print-dead</literal> shows how many bytes would be freed
+      by an actual garbage collection.</para></listitem>
+
+      <listitem><para><literal>nix-collect-garbage -d</literal>
+      removes all old generations of <emphasis>all</emphasis> profiles
+      before calling the actual garbage collector (<literal>nix-store
+      --gc</literal>).  This is an easy way to get rid of all old
+      packages in the Nix store.</para></listitem>
+
+      <listitem><para><command>nix-store</command> now has an
+      operation <option>--delete</option> to delete specific paths
+      from the Nix store.  It won’t delete reachable (non-garbage)
+      paths unless <option>--ignore-liveness</option> is
+      specified.</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para>Berkeley DB 4.4’s process registry feature is used
+  to recover from crashed Nix processes.</para></listitem>
+
+  <!--  <listitem><para>TODO: shared stores.</para></listitem> -->
+
+  <listitem><para>A performance issue has been fixed with the
+  <literal>referer</literal> table, which stores the inverse of the
+  <literal>references</literal> table (i.e., it tells you what store
+  paths refer to a given path).  Maintaining this table could take a
+  quadratic amount of time, as well as a quadratic amount of Berkeley
+  DB log file space (in particular when running the garbage collector)
+  (<literal>NIX-23</literal>).</para></listitem>
+
+  <listitem><para>Nix now catches the <literal>TERM</literal> and
+  <literal>HUP</literal> signals in addition to the
+  <literal>INT</literal> signal.  So you can now do a <literal>killall
+  nix-store</literal> without triggering a database
+  recovery.</para></listitem>
+
+  <listitem><para><command>bsdiff</command> updated to version
+  4.3.</para></listitem>
+
+  <listitem><para>Substantial performance improvements in expression
+  evaluation and <literal>nix-env -qa</literal>, all thanks to <link
+  xlink:href="http://valgrind.org/">Valgrind</link>.  Memory use has
+  been reduced by a factor 8 or so.  Big speedup by memoisation of
+  path hashing.</para></listitem>
+
+  <listitem><para>Lots of bug fixes, notably:
+
+    <itemizedlist>
+
+      <listitem><para>Make sure that the garbage collector can run
+      successfully when the disk is full
+      (<literal>NIX-18</literal>).</para></listitem>
+
+      <listitem><para><command>nix-env</command> now locks the profile
+      to prevent races between concurrent <command>nix-env</command>
+      operations on the same profile
+      (<literal>NIX-7</literal>).</para></listitem>
+
+      <listitem><para>Removed misleading messages from
+      <literal>nix-env -i</literal> (e.g., <literal>installing
+      `foo'</literal> followed by <literal>uninstalling
+      `foo'</literal>) (<literal>NIX-17</literal>).</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+  <listitem><para>Nix source distributions are a lot smaller now since
+  we no longer include a full copy of the Berkeley DB source
+  distribution (but only the bits we need).</para></listitem>
+
+  <listitem><para>Header files are now installed so that external
+  programs can use the Nix libraries.</para></listitem>
+
+</itemizedlist>
+
+</section>
@@ -0,0 +1,261 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-relnotes-0.11">
+
+<title>Release 0.11 (2007-12-31)</title>
+
+<para>Nix 0.11 has many improvements over the previous stable release.
+The most important improvement is secure multi-user support.  It also
+features many usability enhancements and language extensions, many of
+them prompted by NixOS, the purely functional Linux distribution based
+on Nix.  Here is an (incomplete) list:</para>
+
+
+<itemizedlist>
+
+
+  <listitem><para>Secure multi-user support.  A single Nix store can
+  now be shared between multiple (possible untrusted) users.  This is
+  an important feature for NixOS, where it allows non-root users to
+  install software.  The old setuid method for sharing a store between
+  multiple users has been removed.  Details for setting up a
+  multi-user store can be found in the manual.</para></listitem>
+
+
+  <listitem><para>The new command <command>nix-copy-closure</command>
+  gives you an easy and efficient way to exchange software between
+  machines.  It copies the missing parts of the closure of a set of
+  store path to or from a remote machine via
+  <command>ssh</command>.</para></listitem>
+
+
+  <listitem><para>A new kind of string literal: strings between double
+  single-quotes (<literal>''</literal>) have indentation
+  “intelligently” removed.  This allows large strings (such as shell
+  scripts or configuration file fragments in NixOS) to cleanly follow
+  the indentation of the surrounding expression.  It also requires
+  much less escaping, since <literal>''</literal> is less common in
+  most languages than <literal>"</literal>.</para></listitem>
+
+
+  <listitem><para><command>nix-env</command> <option>--set</option>
+  modifies the current generation of a profile so that it contains
+  exactly the specified derivation, and nothing else.  For example,
+  <literal>nix-env -p /nix/var/nix/profiles/browser --set
+  firefox</literal> lets the profile named
+  <filename>browser</filename> contain just Firefox.</para></listitem>
+
+
+  <listitem><para><command>nix-env</command> now maintains
+  meta-information about installed packages in profiles.  The
+  meta-information is the contents of the <varname>meta</varname>
+  attribute of derivations, such as <varname>description</varname> or
+  <varname>homepage</varname>.  The command <literal>nix-env -q --xml
+  --meta</literal> shows all meta-information.</para></listitem>
+
+
+  <listitem><para><command>nix-env</command> now uses the
+  <varname>meta.priority</varname> attribute of derivations to resolve
+  filename collisions between packages.  Lower priority values denote
+  a higher priority.  For instance, the GCC wrapper package and the
+  Binutils package in Nixpkgs both have a file
+  <filename>bin/ld</filename>, so previously if you tried to install
+  both you would get a collision.  Now, on the other hand, the GCC
+  wrapper declares a higher priority than Binutils, so the former’s
+  <filename>bin/ld</filename> is symlinked in the user
+  environment.</para></listitem>
+
+
+  <listitem><para><command>nix-env -i / -u</command>: instead of
+  breaking package ties by version, break them by priority and version
+  number.  That is, if there are multiple packages with the same name,
+  then pick the package with the highest priority, and only use the
+  version if there are multiple packages with the same
+  priority.</para>
+
+  <para>This makes it possible to mark specific versions/variant in
+  Nixpkgs more or less desirable than others.  A typical example would
+  be a beta version of some package (e.g.,
+  <literal>gcc-4.2.0rc1</literal>) which should not be installed even
+  though it is the highest version, except when it is explicitly
+  selected (e.g., <literal>nix-env -i
+  gcc-4.2.0rc1</literal>).</para></listitem>
+
+
+  <listitem><para><command>nix-env --set-flag</command> allows meta
+  attributes of installed packages to be modified.  There are several
+  attributes that can be usefully modified, because they affect the
+  behaviour of <command>nix-env</command> or the user environment
+  build script:
+
+    <itemizedlist>
+
+      <listitem><para><varname>meta.priority</varname> can be changed
+      to resolve filename clashes (see above).</para></listitem>
+
+      <listitem><para><varname>meta.keep</varname> can be set to
+      <literal>true</literal> to prevent the package from being
+      upgraded or replaced.  Useful if you want to hang on to an older
+      version of a package.</para></listitem>
+
+      <listitem><para><varname>meta.active</varname> can be set to
+      <literal>false</literal> to “disable” the package.  That is, no
+      symlinks will be generated to the files of the package, but it
+      remains part of the profile (so it won’t be garbage-collected).
+      Set it back to <literal>true</literal> to re-enable the
+      package.</para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+
+  <listitem><para><command>nix-env -q</command> now has a flag
+  <option>--prebuilt-only</option> (<option>-b</option>) that causes
+  <command>nix-env</command> to show only those derivations whose
+  output is already in the Nix store or that can be substituted (i.e.,
+  downloaded from somewhere).  In other words, it shows the packages
+  that can be installed “quickly”, i.e., don’t need to be built from
+  source.  The <option>-b</option> flag is also available in
+  <command>nix-env -i</command> and <command>nix-env -u</command> to
+  filter out derivations for which no pre-built binary is
+  available.</para></listitem>
+
+
+  <listitem><para>The new option <option>--argstr</option> (in
+  <command>nix-env</command>, <command>nix-instantiate</command> and
+  <command>nix-build</command>) is like <option>--arg</option>, except
+  that the value is a string.  For example, <literal>--argstr system
+  i686-linux</literal> is equivalent to <literal>--arg system
+  \"i686-linux\"</literal> (note that <option>--argstr</option>
+  prevents annoying quoting around shell arguments).</para></listitem>
+
+
+  <listitem><para><command>nix-store</command> has a new operation
+  <option>--read-log</option> (<option>-l</option>)
+  <parameter>paths</parameter> that shows the build log of the given
+  paths.</para></listitem>
+
+
+  <!--
+  <listitem><para>TODO: semantic cleanups of string concatenation
+  etc. (mostly in r6740).</para></listitem>
+  -->
+
+
+  <listitem><para>Nix now uses Berkeley DB 4.5.  The database is
+  upgraded automatically, but you should be careful not to use old
+  versions of Nix that still use Berkeley DB 4.4.</para></listitem>
+
+
+  <!-- foo
+  <listitem><para>TODO: option <option>- -reregister</option> in
+  <command>nix-store - -register-validity</command>.</para></listitem>
+  -->
+
+
+  <listitem><para>The option <option>--max-silent-time</option>
+  (corresponding to the configuration setting
+  <literal>build-max-silent-time</literal>) allows you to set a
+  timeout on builds — if a build produces no output on
+  <literal>stdout</literal> or <literal>stderr</literal> for the given
+  number of seconds, it is terminated.  This is useful for recovering
+  automatically from builds that are stuck in an infinite
+  loop.</para></listitem>
+
+
+  <listitem><para><command>nix-channel</command>: each subscribed
+  channel is its own attribute in the top-level expression generated
+  for the channel.  This allows disambiguation (e.g. <literal>nix-env
+  -i -A nixpkgs_unstable.firefox</literal>).</para></listitem>
+
+
+  <listitem><para>The substitutes table has been removed from the
+  database.  This makes operations such as <command>nix-pull</command>
+  and <command>nix-channel --update</command> much, much
+  faster.</para></listitem>
+
+
+  <listitem><para><command>nix-pull</command> now supports
+  bzip2-compressed manifests.  This speeds up
+  channels.</para></listitem>
+
+
+  <listitem><para><command>nix-prefetch-url</command> now has a
+  limited form of caching.  This is used by
+  <command>nix-channel</command> to prevent unnecessary downloads when
+  the channel hasn’t changed.</para></listitem>
+
+
+  <listitem><para><command>nix-prefetch-url</command> now by default
+  computes the SHA-256 hash of the file instead of the MD5 hash.  In
+  calls to <function>fetchurl</function> you should pass the
+  <literal>sha256</literal> attribute instead of
+  <literal>md5</literal>.  You can pass either a hexadecimal or a
+  base-32 encoding of the hash.</para></listitem>
+
+
+  <listitem><para>Nix can now perform builds in an automatically
+  generated “chroot”.  This prevents a builder from accessing stuff
+  outside of the Nix store, and thus helps ensure purity.  This is an
+  experimental feature.</para></listitem>
+
+
+  <listitem><para>The new command <command>nix-store
+  --optimise</command> reduces Nix store disk space usage by finding
+  identical files in the store and hard-linking them to each other.
+  It typically reduces the size of the store by something like
+  25-35%.</para></listitem>
+
+
+  <listitem><para><filename>~/.nix-defexpr</filename> can now be a
+  directory, in which case the Nix expressions in that directory are
+  combined into an attribute set, with the file names used as the
+  names of the attributes.  The command <command>nix-env
+  --import</command> (which set the
+  <filename>~/.nix-defexpr</filename> symlink) is
+  removed.</para></listitem>
+
+
+  <listitem><para>Derivations can specify the new special attribute
+  <varname>allowedReferences</varname> to enforce that the references
+  in the output of a derivation are a subset of a declared set of
+  paths.  For example, if <varname>allowedReferences</varname> is an
+  empty list, then the output must not have any references.  This is
+  used in NixOS to check that generated files such as initial ramdisks
+  for booting Linux don’t have any dependencies.</para></listitem>
+
+
+  <listitem><para>The new attribute
+  <varname>exportReferencesGraph</varname> allows builders access to
+  the references graph of their inputs.  This is used in NixOS for
+  tasks such as generating ISO-9660 images that contain a Nix store
+  populated with the closure of certain paths.</para></listitem>
+
+
+  <listitem><para>Fixed-output derivations (like
+  <function>fetchurl</function>) can define the attribute
+  <varname>impureEnvVars</varname> to allow external environment
+  variables to be passed to builders.  This is used in Nixpkgs to
+  support proxy configuration, among other things.</para></listitem>
+
+
+  <listitem><para>Several new built-in functions:
+  <function>builtins.attrNames</function>,
+  <function>builtins.filterSource</function>,
+  <function>builtins.isAttrs</function>,
+  <function>builtins.isFunction</function>,
+  <function>builtins.listToAttrs</function>,
+  <function>builtins.stringLength</function>,
+  <function>builtins.sub</function>,
+  <function>builtins.substring</function>,
+  <function>throw</function>,
+  <function>builtins.trace</function>,
+  <function>builtins.readFile</function>.</para></listitem>
+
+
+</itemizedlist>
+
+</section>
@@ -0,0 +1,175 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-relnotes-0.12">
+
+<title>Release 0.12 (2008-11-20)</title>
+
+<itemizedlist>
+
+  <listitem>
+    <para>Nix no longer uses Berkeley DB to store Nix store metadata.
+    The principal advantages of the new storage scheme are: it works
+    properly over decent implementations of NFS (allowing Nix stores
+    to be shared between multiple machines); no recovery is needed
+    when a Nix process crashes; no write access is needed for
+    read-only operations; no more running out of Berkeley DB locks on
+    certain operations.</para>
+
+    <para>You still need to compile Nix with Berkeley DB support if
+    you want Nix to automatically convert your old Nix store to the
+    new schema.  If you don’t need this, you can build Nix with the
+    <filename>configure</filename> option
+    <option>--disable-old-db-compat</option>.</para>
+
+    <para>After the automatic conversion to the new schema, you can
+    delete the old Berkeley DB files:
+
+    <screen>
+$ cd /nix/var/nix/db
+$ rm __db* log.* derivers references referrers reserved validpaths DB_CONFIG</screen>
+
+    The new metadata is stored in the directories
+    <filename>/nix/var/nix/db/info</filename> and
+    <filename>/nix/var/nix/db/referrer</filename>.  Though the
+    metadata is stored in human-readable plain-text files, they are
+    not intended to be human-editable, as Nix is rather strict about
+    the format.</para>
+
+    <para>The new storage schema may or may not require less disk
+    space than the Berkeley DB environment, mostly depending on the
+    cluster size of your file system.  With 1 KiB clusters (which
+    seems to be the <literal>ext3</literal> default nowadays) it
+    usually takes up much less space.</para>
+  </listitem>
+
+  <listitem><para>There is a new substituter that copies paths
+  directly from other (remote) Nix stores mounted somewhere in the
+  filesystem.  For instance, you can speed up an installation by
+  mounting some remote Nix store that already has the packages in
+  question via NFS or <literal>sshfs</literal>.  The environment
+  variable <envar>NIX_OTHER_STORES</envar> specifies the locations of
+  the remote Nix directories,
+  e.g. <literal>/mnt/remote-fs/nix</literal>.</para></listitem>
+
+  <listitem><para>New <command>nix-store</command> operations
+  <option>--dump-db</option> and <option>--load-db</option> to dump
+  and reload the Nix database.</para></listitem>
+
+  <listitem><para>The garbage collector has a number of new options to
+  allow only some of the garbage to be deleted.  The option
+  <option>--max-freed <replaceable>N</replaceable></option> tells the
+  collector to stop after at least <replaceable>N</replaceable> bytes
+  have been deleted.  The option <option>--max-links
+  <replaceable>N</replaceable></option> tells it to stop after the
+  link count on <filename>/nix/store</filename> has dropped below
+  <replaceable>N</replaceable>.  This is useful for very large Nix
+  stores on filesystems with a 32000 subdirectories limit (like
+  <literal>ext3</literal>).  The option <option>--use-atime</option>
+  causes store paths to be deleted in order of ascending last access
+  time.  This allows non-recently used stuff to be deleted.  The
+  option <option>--max-atime <replaceable>time</replaceable></option>
+  specifies an upper limit to the last accessed time of paths that may
+  be deleted.  For instance,
+
+    <screen>
+    $ nix-store --gc -v --max-atime $(date +%s -d "2 months ago")</screen>
+
+  deletes everything that hasn’t been accessed in two months.</para></listitem>
+
+  <listitem><para><command>nix-env</command> now uses optimistic
+  profile locking when performing an operation like installing or
+  upgrading, instead of setting an exclusive lock on the profile.
+  This allows multiple <command>nix-env -i / -u / -e</command>
+  operations on the same profile in parallel.  If a
+  <command>nix-env</command> operation sees at the end that the profile
+  was changed in the meantime by another process, it will just
+  restart.  This is generally cheap because the build results are
+  still in the Nix store.</para></listitem>
+
+  <listitem><para>The option <option>--dry-run</option> is now
+  supported by <command>nix-store -r</command> and
+  <command>nix-build</command>.</para></listitem>
+
+  <listitem><para>The information previously shown by
+  <option>--dry-run</option> (i.e., which derivations will be built
+  and which paths will be substituted) is now always shown by
+  <command>nix-env</command>, <command>nix-store -r</command> and
+  <command>nix-build</command>.  The total download size of
+  substitutable paths is now also shown.  For instance, a build will
+  show something like
+
+    <screen>
+the following derivations will be built:
+  /nix/store/129sbxnk5n466zg6r1qmq1xjv9zymyy7-activate-configuration.sh.drv
+  /nix/store/7mzy971rdm8l566ch8hgxaf89x7lr7ik-upstart-jobs.drv
+  ...
+the following paths will be downloaded/copied (30.02 MiB):
+  /nix/store/4m8pvgy2dcjgppf5b4cj5l6wyshjhalj-samba-3.2.4
+  /nix/store/7h1kwcj29ip8vk26rhmx6bfjraxp0g4l-libunwind-0.98.6
+  ...</screen>
+
+  </para></listitem>
+
+  <listitem><para>Language features:
+
+    <itemizedlist>
+
+      <listitem><para>@-patterns as in Haskell.  For instance, in a
+      function definition
+
+      <programlisting>f = args @ {x, y, z}: <replaceable>...</replaceable>;</programlisting>
+
+      <varname>args</varname> refers to the argument as a whole, which
+      is further pattern-matched against the attribute set pattern
+      <literal>{x, y, z}</literal>.</para></listitem>
+
+      <listitem><para>“<literal>...</literal>” (ellipsis) patterns.
+      An attribute set pattern can now say <literal>...</literal>  at
+      the end of the attribute name list to specify that the function
+      takes <emphasis>at least</emphasis> the listed attributes, while
+      ignoring additional attributes.  For instance,
+
+      <programlisting>{stdenv, fetchurl, fuse, ...}: <replaceable>...</replaceable></programlisting>
+
+      defines a function that accepts any attribute set that includes
+      at least the three listed attributes.</para></listitem>
+
+      <listitem><para>New primops:
+      <varname>builtins.parseDrvName</varname> (split a package name
+      string like <literal>"nix-0.12pre12876"</literal> into its name
+      and version components, e.g. <literal>"nix"</literal> and
+      <literal>"0.12pre12876"</literal>),
+      <varname>builtins.compareVersions</varname> (compare two version
+      strings using the same algorithm that <command>nix-env</command>
+      uses), <varname>builtins.length</varname> (efficiently compute
+      the length of a list), <varname>builtins.mul</varname> (integer
+      multiplication), <varname>builtins.div</varname> (integer
+      division).
+      <!-- <varname>builtins.genericClosure</varname> -->
+      </para></listitem>
+
+    </itemizedlist>
+
+  </para></listitem>
+
+  <listitem><para><command>nix-prefetch-url</command> now supports
+  <literal>mirror://</literal> URLs, provided that the environment
+  variable <envar>NIXPKGS_ALL</envar> points at a Nixpkgs
+  tree.</para></listitem>
+
+  <listitem><para>Removed the commands
+  <command>nix-pack-closure</command> and
+  <command>nix-unpack-closure</command>.   You can do almost the same
+  thing but much more efficiently by doing <literal>nix-store --export
+  $(nix-store -qR <replaceable>paths</replaceable>) > closure</literal> and
+  <literal>nix-store --import &lt;
+  closure</literal>.</para></listitem>
+
+  <listitem><para>Lots of bug fixes, including a big performance bug in
+  the handling of <literal>with</literal>-expressions.</para></listitem>
+
+</itemizedlist>
+
+</section>
@@ -0,0 +1,106 @@
+<section xmlns="http://docbook.org/ns/docbook"
+      xmlns:xlink="http://www.w3.org/1999/xlink"
+      xmlns:xi="http://www.w3.org/2001/XInclude"
+      version="5.0"
+      xml:id="ssec-relnotes-0.13">
+
+<title>Release 0.13 (2009-11-05)</title>
+
+<para>This is primarily a bug fix release.  It has some new
+features:</para>
+
+<itemizedlist>
+
+  <listitem>
+    <para>Syntactic sugar for writing nested attribute sets.  Instead of
+
+<programlisting>
+{
+  foo = {
+    bar = 123;
+    xyzzy = true;
+  };
+  a = { b = { c = "d"; }; };
+}
+</programlisting>
+
+    you can write
+
+<programlisting>
+{
+  foo.bar = 123;
+  foo.xyzzy = true;
+  a.b.c = "d";
+}
+</programlisting>
+
+    This is useful, for instance, in NixOS configuration files.</para>
+
+  </listitem>
+
+  <listitem>
+    <para>Support for Nix channels generated by Hydra, the Nix-based
+    continuous build system.  (Hydra generates NAR archives on the
+    fly, so the size and hash of these archives isn’t known in
+    advance.)</para>
+  </listitem>
+
+  <listitem>
+    <para>Support <literal>i686-linux</literal> builds directly on
+    <literal>x86_64-linux</literal> Nix installations.  This is
+    implemented using the <function>personality()</function> syscall,
+    which causes <command>uname</command> to return
+    <literal>i686</literal> in child processes.</para>
+  </listitem>
+
+  <listitem>
+    <para>Various improvements to the <literal>chroot</literal>
+    support.  Building in a <literal>chroot</literal> works quite well
+    now.</para>
+  </listitem>
+
+  <listitem>
+    <para>Nix no longer blocks if it tries to build a path and another
+    process is already building the same path.  Instead it tries to
+    build another buildable path first.  This improves
+    parallelism.</para>
+  </listitem>
+
+  <listitem>
+    <para>Support for large (> 4 GiB) files in NAR archives.</para>
+  </listitem>
+
+  <listitem>
+    <para>Various (performance) improvements to the remote build
+    mechanism.</para>
+  </listitem>
+
+  <listitem>
+    <para>New primops: <varname>builtins.addErrorContext</varname> (to
+    add a string to stack traces — useful for debugging),
+    <varname>builtins.isBool</varname>,
+    <varname>builtins.isString</varname>,
+    <varname>builtins.isInt</varname>,
+    <varname>builtins.intersectAttrs</varname>.</para>
+  </listitem>
+
+  <listitem>
+    <para>OpenSolaris support (Sander van der Burg).</para>
+  </listitem>
+
+  <listitem>
+    <para>Stack traces are no longer displayed unless the
+    <option>--show-trace</option> option is used.</para>
+  </listitem>
+
+  <listitem>
+    <para>The scoping rules for <literal>inherit
+    (<replaceable>e</replaceable>) ...</literal> in recursive
+    attribute sets have changed.  The expression
+    <replaceable>e</replaceable> can now refer to the attributes
+    defined in the containing set.</para>
+  </listitem>
+
+</itemizedlist>
+
+</section>