Merge remote-tracking branch 'origin/master' into cross-jobs

2021-02-05 18:07:48 -06:00 · 2021-02-05 18:07:48 -06:00 · c6d878609d
parent f6ea56dfac 480426a364
commit c6d878609d
785 changed files with 58828 additions and 56249 deletions
--- a/.dir-locals.el
+++ b/.dir-locals.el
@ -1,6 +1,7 @@
 ((c++-mode . (
  (c-file-style . "k&r")
  (c-basic-offset . 4)
  (c-block-comment-prefix . "  ")
  (indent-tabs-mode . nil)
  (tab-width . 4)
  (show-trailing-whitespace . t)
@ -13,4 +14,5 @@
  (eval . (c-set-offset 'arglist-cont-nonempty '+))
  (eval . (c-set-offset 'substatement-open 0))
  (eval . (c-set-offset 'access-label '-))
  (eval . (c-set-offset 'inlambda 0))
  )))
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@ -1,27 +0,0 @@
 <!--
 # Filing a Nix issue
 *WAIT* Are you sure you're filing your issue in the right repository?
 We appreciate you taking the time to tell us about issues you encounter, but routing the issue to the right place will get you help sooner and save everyone time.
 This is the Nix repository, and issues here should be about Nix the build and package management *_tool_*.
 If you have a problem with a specific package on NixOS or when using Nix, you probably want to file an issue with _nixpkgs_, whose issue tracker is over at https://github.com/NixOS/nixpkgs/issues.
 Examples of _Nix_ issues:
 - Nix segfaults when I run `nix-build -A blahblah`
 - The Nix language needs a new builtin: `builtins.foobar`
 - Regression in the behavior of `nix-env` in Nix 2.0
 Examples of _nixpkgs_ issues:
 - glibc is b0rked on aarch64
 - chromium in NixOS doesn't support U2F but google-chrome does!
 - The OpenJDK package on macOS is missing a key component
 Chances are if you're a newcomer to the Nix world, you'll probably want the [nixpkgs tracker](https://github.com/NixOS/nixpkgs/issues). It also gets a lot more eyeball traffic so you'll probably get a response a lot more quickly.
 -->
--- a/.github/ISSUE_TEMPLATE/bug_report.md
+++ b/.github/ISSUE_TEMPLATE/bug_report.md
@ -0,0 +1,32 @@
 ---
 name: Bug report
 about: Create a report to help us improve
 title: ''
 labels: bug
 assignees: ''
 ---
 **Describe the bug**
 A clear and concise description of what the bug is.
 If you have a problem with a specific package or NixOS,
 you probably want to file an issue at https://github.com/NixOS/nixpkgs/issues. 
 **Steps To Reproduce**
 1. Go to '...'
 2. Click on '....'
 3. Scroll down to '....'
 4. See error
 **Expected behavior**
 A clear and concise description of what you expected to happen.
 **`nix-env --version` output**
 **Additional context**
 Add any other context about the problem here.
--- a/.github/ISSUE_TEMPLATE/feature_request.md
+++ b/.github/ISSUE_TEMPLATE/feature_request.md
@ -0,0 +1,20 @@
 ---
 name: Feature request
 about: Suggest an idea for this project
 title: ''
 labels: improvement
 assignees: ''
 ---
 **Is your feature request related to a problem? Please describe.**
 A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
 **Describe the solution you'd like**
 A clear and concise description of what you want to happen.
 **Describe alternatives you've considered**
 A clear and concise description of any alternative solutions or features you've considered.
 **Additional context**
 Add any other context or screenshots about the feature request here.
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -0,0 +1,6 @@
 version: 2
 updates:
  - package-ecosystem: "github-actions"
    directory: "/"
    schedule:
      interval: "weekly"
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@ -0,0 +1,17 @@
 name: "Test"
 on:
  pull_request:
  push:
 jobs:
  tests:
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
    runs-on: ${{ matrix.os }}
    steps:
    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
    - uses: cachix/install-nix-action@v12
    #- run: nix flake check
    - run: nix-build -A checks.$(if [[ `uname` = Linux ]]; then echo x86_64-linux; else echo x86_64-darwin; fi)
--- a/.gitignore
+++ b/.gitignore
@ -4,35 +4,27 @@ perl/Makefile.config
 # /
 /aclocal.m4
 /autom4te.cache
 /precompiled-headers.h.gch
 /config.*
 /configure
 /nix.spec
 /stamp-h1
 /svn-revision
 /libtool
 /corepkgs/config.nix
 # /corepkgs/channels/
 /corepkgs/channels/unpack.sh
 # /corepkgs/nar/
 /corepkgs/nar/nar.sh
 /corepkgs/nar/unnar.sh
 # /doc/manual/
 /doc/manual/manual.html
 /doc/manual/manual.xmli
 /doc/manual/manual.pdf
 /doc/manual/manual.is-valid
 /doc/manual/*.1
 /doc/manual/*.5
 /doc/manual/*.8
-/doc/manual/version.txt
+/doc/manual/nix.json
 /doc/manual/conf-file.json
 /doc/manual/builtins.json
 /doc/manual/src/SUMMARY.md
 /doc/manual/src/command-ref/new-cli
 /doc/manual/src/command-ref/conf-file.md
 /doc/manual/src/expressions/builtins.md
 # /scripts/
 /scripts/nix-profile.sh
 /scripts/nix-copy-closure
 /scripts/nix-reduce-build
 /scripts/nix-http-export.cgi
 /scripts/nix-profile-daemon.sh
@ -46,7 +38,10 @@ perl/Makefile.config
 /src/libexpr/nix.tbl
 # /src/libstore/
-/src/libstore/*.gen.hh
+*.gen.*
 # /src/libutil/
 /src/libutil/tests/libutil-tests
 /src/nix/nix
@ -74,6 +69,8 @@ perl/Makefile.config
 /src/nix-copy-closure/nix-copy-closure
 /src/error-demo/error-demo
 /src/build-remote/build-remote
 # /tests/
@ -81,6 +78,10 @@ perl/Makefile.config
 /tests/common.sh
 /tests/dummy
 /tests/result*
 /tests/restricted-innocent
 /tests/shell
 /tests/shell.drv
 /tests/config.nix
 # /tests/lang/
 /tests/lang/*.out
@ -96,7 +97,7 @@ perl/Makefile.config
 /src/resolve-system-dependencies/resolve-system-dependencies
-inst/
+outputs/
 *.a
 *.o
@ -114,3 +115,11 @@ GPATH
 GRTAGS
 GSYMS
 GTAGS
 # ccls
 /.ccls-cache
 # auto-generated compilation database
 compile_commands.json
 nix-rust/target
--- a/.travis.yml
+++ b/.travis.yml
@ -1,2 +0,0 @@
 os: osx
 script: ./tests/install-darwin.sh
--- a/.version
+++ b/.version
@ -0,0 +1 @@
 2.4
--- a/13
+++ b/13
@ -1,13 +1,17 @@
 makefiles = \
  mk/precompiled-headers.mk \
  local.mk \
  src/libutil/local.mk \
  src/libutil/tests/local.mk \
  src/libstore/local.mk \
  src/libfetchers/local.mk \
  src/libmain/local.mk \
  src/libexpr/local.mk \
  src/libcmd/local.mk \
  src/nix/local.mk \
  src/resolve-system-dependencies/local.mk \
  scripts/local.mk \
-  corepkgs/local.mk \
+  misc/bash/local.mk \
  misc/systemd/local.mk \
  misc/launchd/local.mk \
  misc/upstart/local.mk \
@ -15,15 +19,16 @@ makefiles = \
  tests/local.mk \
  tests/plugins/local.mk
 GLOBAL_CXXFLAGS += -g -Wall -include config.h
 -include Makefile.config
 OPTIMIZE = 1
 ifeq ($(OPTIMIZE), 1)
  GLOBAL_CFLAGS += -O3
  GLOBAL_CXXFLAGS += -O3
 else
  GLOBAL_CXXFLAGS += -O0 -U_FORTIFY_SOURCE
 endif
 include mk/lib.mk
 GLOBAL_CXXFLAGS += -g -Wall -include config.h -std=c++17
--- a/Makefile.config.in
+++ b/Makefile.config.in
@ -1,38 +1,42 @@
 AR = @AR@
 BDW_GC_LIBS = @BDW_GC_LIBS@
 BOOST_LDFLAGS = @BOOST_LDFLAGS@
 BUILD_SHARED_LIBS = @BUILD_SHARED_LIBS@
 CC = @CC@
 CFLAGS = @CFLAGS@
 CXX = @CXX@
 CXXFLAGS = @CXXFLAGS@
 EDITLINE_LIBS = @EDITLINE_LIBS@
 ENABLE_S3 = @ENABLE_S3@
-HAVE_SODIUM = @HAVE_SODIUM@
+GTEST_LIBS = @GTEST_LIBS@
 HAVE_READLINE = @HAVE_READLINE@
 HAVE_SECCOMP = @HAVE_SECCOMP@
 LDFLAGS = @LDFLAGS@
 LIBARCHIVE_LIBS = @LIBARCHIVE_LIBS@
 LIBBROTLI_LIBS = @LIBBROTLI_LIBS@
 LIBCURL_LIBS = @LIBCURL_LIBS@
 LIBLZMA_LIBS = @LIBLZMA_LIBS@
 OPENSSL_LIBS = @OPENSSL_LIBS@
 PACKAGE_NAME = @PACKAGE_NAME@
 PACKAGE_VERSION = @PACKAGE_VERSION@
 SHELL = @bash@
 SODIUM_LIBS = @SODIUM_LIBS@
 LIBLZMA_LIBS = @LIBLZMA_LIBS@
 SQLITE3_LIBS = @SQLITE3_LIBS@
 LIBBROTLI_LIBS = @LIBBROTLI_LIBS@
 EDITLINE_LIBS = @EDITLINE_LIBS@
 bash = @bash@
 bindir = @bindir@
 lsof = @lsof@
 datadir = @datadir@
 datarootdir = @datarootdir@
 doc_generate = @doc_generate@
 docdir = @docdir@
 exec_prefix = @exec_prefix@
 includedir = @includedir@
 libdir = @libdir@
 libexecdir = @libexecdir@
 localstatedir = @localstatedir@
 lsof = @lsof@
 mandir = @mandir@
 pkglibdir = $(libdir)/$(PACKAGE_NAME)
 prefix = @prefix@
 sandbox_shell = @sandbox_shell@
 storedir = @storedir@
 sysconfdir = @sysconfdir@
-doc_generate = @doc_generate@
+system = @system@
 xmllint = @xmllint@
 xsltproc = @xsltproc@
--- a/README.md
+++ b/README.md
@ -1,22 +1,35 @@
-Nix, the purely functional package manager
+# Nix
 ------------------------------------------
-Nix is a new take on package management that is fairly unique. Because of its
+[![Open Collective supporters](https://opencollective.com/nixos/tiers/supporter/badge.svg?label=Supporters&color=brightgreen)](https://opencollective.com/nixos)
-purity aspects, a lot of issues found in traditional package managers don't
+[![Test](https://github.com/NixOS/nix/workflows/Test/badge.svg)](https://github.com/NixOS/nix/actions)
 appear with Nix.
-To find out more about the tool, usage and installation instructions, please
+Nix is a powerful package manager for Linux and other Unix systems that makes package
-read the manual, which is available on the Nix website at
+management reliable and reproducible. Please refer to the [Nix manual](https://nixos.org/nix/manual)
-<http://nixos.org/nix/manual>.
+for more details.
-## Contributing
+## Installation
-Take a look at the [Hacking Section](http://nixos.org/nix/manual/#chap-hacking)
+On Linux and macOS the easiest way to install Nix is to run the following shell command
-of the manual. It helps you to get started with building Nix from source.
+(as a user other than root):
 ```console
 $ curl -L https://nixos.org/nix/install | sh
 ```
 Information on additional installation methods is available on the [Nix download page](https://nixos.org/download.html).
 ## Building And Developing
 See our [Hacking guide](https://hydra.nixos.org/job/nix/master/build.x86_64-linux/latest/download-by-type/doc/manual/contributing/hacking.html) in our manual for instruction on how to
 build nix from source with nix-build or how to get a development environment.
 ## Additional Resources
 - [Nix manual](https://nixos.org/nix/manual)
 - [Nix jobsets on hydra.nixos.org](https://hydra.nixos.org/project/nix)
 - [NixOS Discourse](https://discourse.nixos.org/)
 - [IRC - #nixos on freenode.net](irc://irc.freenode.net/#nixos)
 ## License
-Nix is released under the LGPL v2.1
+Nix is released under the [LGPL v2.1](./COPYING).
 This product includes software developed by the OpenSSL Project for
 use in the [OpenSSL Toolkit](http://www.OpenSSL.org/).
--- a/config/config.guess
+++ b/config/config.guess
@ -1,8 +1,8 @@
 #! /bin/sh
 # Attempt to guess a canonical system name.
-#   Copyright 1992-2018 Free Software Foundation, Inc.
+#   Copyright 1992-2020 Free Software Foundation, Inc.
-timestamp='2018-08-02'
+timestamp='2020-11-19'
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@ -27,12 +27,12 @@ timestamp='2018-08-02'
 # Originally written by Per Bothner; maintained since 2000 by Ben Elliston.
 #
 # You can get the latest version of this script from:
-# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+# https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
 #
 # Please send patches to <config-patches@gnu.org>.
-me=`echo "$0" | sed -e 's,.*/,,'`
+me=$(echo "$0" | sed -e 's,.*/,,')
 usage="\
 Usage: $0 [OPTION]
@ -50,7 +50,7 @@ version="\
 GNU config.guess ($timestamp)
 Originally written by Per Bothner.
-Copyright 1992-2018 Free Software Foundation, Inc.
+Copyright 1992-2020 Free Software Foundation, Inc.
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@ -96,13 +96,14 @@ fi
 tmp=
 # shellcheck disable=SC2172
-trap 'test -z "$tmp" || rm -fr "$tmp"' 1 2 13 15
+trap 'test -z "$tmp" || rm -fr "$tmp"' 0 1 2 13 15
 trap 'exitcode=$?; test -z "$tmp" || rm -fr "$tmp"; exit $exitcode' 0
 set_cc_for_build() {
    # prevent multiple calls if $tmp is already set
    test "$tmp" && return 0
    : "${TMPDIR=/tmp}"
    # shellcheck disable=SC2039
-    { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
+    { tmp=$( (umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null) && test -n "$tmp" && test -d "$tmp" ; } ||
 	{ test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir "$tmp" 2>/dev/null) ; } ||
 	{ tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir "$tmp" 2>/dev/null) && echo "Warning: creating insecure temp directory" >&2 ; } ||
 	{ echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; }
@ -130,16 +131,14 @@ if test -f /.attbin/uname ; then
 	PATH=$PATH:/.attbin ; export PATH
 fi
-UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
+UNAME_MACHINE=$( (uname -m) 2>/dev/null) || UNAME_MACHINE=unknown
-UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
+UNAME_RELEASE=$( (uname -r) 2>/dev/null) || UNAME_RELEASE=unknown
-UNAME_SYSTEM=`(uname -s) 2>/dev/null`  || UNAME_SYSTEM=unknown
+UNAME_SYSTEM=$( (uname -s) 2>/dev/null) || UNAME_SYSTEM=unknown
-UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
+UNAME_VERSION=$( (uname -v) 2>/dev/null) || UNAME_VERSION=unknown
 case "$UNAME_SYSTEM" in
 Linux|GNU|GNU/*)
-	# If the system lacks a compiler, then just pick glibc.
+	LIBC=unknown
 	# We could probably try harder.
 	LIBC=gnu
 	set_cc_for_build
 	cat <<-EOF > "$dummy.c"
@ -148,17 +147,29 @@ Linux|GNU|GNU/*)
 	LIBC=uclibc
 	#elif defined(__dietlibc__)
 	LIBC=dietlibc
-	#else
+	#elif defined(__GLIBC__)
 	LIBC=gnu
 	#else
 	#include <stdarg.h>
 	/* First heuristic to detect musl libc.  */
 	#ifdef __DEFINED_va_list
 	LIBC=musl
 	#endif
 	#endif
 	EOF
-	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g'`"
+	eval "$($CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g')"
-	# If ldd exists, use it to detect musl libc.
+	# Second heuristic to detect musl libc.
-	if command -v ldd >/dev/null && \
+	if [ "$LIBC" = unknown ] &&
-		ldd --version 2>&1 | grep -q ^musl
+	   command -v ldd >/dev/null &&
-	then
+	   ldd --version 2>&1 | grep -q ^musl; then
-	    LIBC=musl
+		LIBC=musl
 	fi
 	# If the system lacks a compiler, then just pick glibc.
 	# We could probably try harder.
 	if [ "$LIBC" = unknown ]; then
 		LIBC=gnu
 	fi
 	;;
 esac
@ -178,19 +189,20 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	# Note: NetBSD doesn't particularly care about the vendor
 	# portion of the name.  We always set it to "unknown".
 	sysctl="sysctl -n hw.machine_arch"
-	UNAME_MACHINE_ARCH=`(uname -p 2>/dev/null || \
+	UNAME_MACHINE_ARCH=$( (uname -p 2>/dev/null || \
 	    "/sbin/$sysctl" 2>/dev/null || \
 	    "/usr/sbin/$sysctl" 2>/dev/null || \
-	    echo unknown)`
+	    echo unknown))
 	case "$UNAME_MACHINE_ARCH" in
 	    aarch64eb) machine=aarch64_be-unknown ;;
 	    armeb) machine=armeb-unknown ;;
 	    arm*) machine=arm-unknown ;;
 	    sh3el) machine=shl-unknown ;;
 	    sh3eb) machine=sh-unknown ;;
 	    sh5el) machine=sh5le-unknown ;;
 	    earmv*)
-		arch=`echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,'`
+		arch=$(echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,')
-		endian=`echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p'`
+		endian=$(echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p')
 		machine="${arch}${endian}"-unknown
 		;;
 	    *) machine="$UNAME_MACHINE_ARCH"-unknown ;;
@ -221,7 +233,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	case "$UNAME_MACHINE_ARCH" in
 	    earm*)
 		expr='s/^earmv[0-9]/-eabi/;s/eb$//'
-		abi=`echo "$UNAME_MACHINE_ARCH" | sed -e "$expr"`
+		abi=$(echo "$UNAME_MACHINE_ARCH" | sed -e "$expr")
 		;;
 	esac
 	# The OS release
@ -234,7 +246,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 		release='-gnu'
 		;;
 	    *)
-		release=`echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2`
+		release=$(echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2)
 		;;
 	esac
 	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
@ -243,15 +255,15 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	echo "$machine-${os}${release}${abi-}"
 	exit ;;
    *:Bitrig:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/Bitrig.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/Bitrig.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-bitrig"$UNAME_RELEASE"
 	exit ;;
    *:OpenBSD:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/OpenBSD.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-openbsd"$UNAME_RELEASE"
 	exit ;;
    *:LibertyBSD:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/^.*BSD\.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/^.*BSD\.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-libertybsd"$UNAME_RELEASE"
 	exit ;;
    *:MidnightBSD:*:*)
@ -263,6 +275,9 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
    *:SolidBSD:*:*)
 	echo "$UNAME_MACHINE"-unknown-solidbsd"$UNAME_RELEASE"
 	exit ;;
    *:OS108:*:*)
 	echo "$UNAME_MACHINE"-unknown-os108_"$UNAME_RELEASE"
 	exit ;;
    macppc:MirBSD:*:*)
 	echo powerpc-unknown-mirbsd"$UNAME_RELEASE"
 	exit ;;
@ -272,26 +287,29 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
    *:Sortix:*:*)
 	echo "$UNAME_MACHINE"-unknown-sortix
 	exit ;;
    *:Twizzler:*:*)
 	echo "$UNAME_MACHINE"-unknown-twizzler
 	exit ;;
    *:Redox:*:*)
 	echo "$UNAME_MACHINE"-unknown-redox
 	exit ;;
    mips:OSF1:*.*)
-        echo mips-dec-osf1
+	echo mips-dec-osf1
-        exit ;;
+	exit ;;
    alpha:OSF1:*:*)
 	case $UNAME_RELEASE in
 	*4.0)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
+		UNAME_RELEASE=$(/usr/sbin/sizer -v | awk '{print $3}')
 		;;
 	*5.*)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
+		UNAME_RELEASE=$(/usr/sbin/sizer -v | awk '{print $4}')
 		;;
 	esac
 	# According to Compaq, /usr/sbin/psrinfo has been available on
 	# OSF/1 and Tru64 systems produced since 1995.  I hope that
 	# covers most systems running today.  This code pipes the CPU
 	# types through head -n 1, so we only detect the type of CPU 0.
-	ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1`
+	ALPHA_CPU_TYPE=$(/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1)
 	case "$ALPHA_CPU_TYPE" in
 	    "EV4 (21064)")
 		UNAME_MACHINE=alpha ;;
@ -329,7 +347,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	# A Tn.n version is a released field test version.
 	# A Xn.n version is an unreleased experimental baselevel.
 	# 1.2 uses "1.2" for uname -r.
-	echo "$UNAME_MACHINE"-dec-osf"`echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`"
+	echo "$UNAME_MACHINE"-dec-osf"$(echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz)"
 	# Reset EXIT trap before exiting to avoid spurious non-zero exit code.
 	exitcode=$?
 	trap '' 0
@ -363,7 +381,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	exit ;;
    Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
 	# akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
-	if test "`(/bin/universe) 2>/dev/null`" = att ; then
+	if test "$( (/bin/universe) 2>/dev/null)" = att ; then
 		echo pyramid-pyramid-sysv3
 	else
 		echo pyramid-pyramid-bsd
@ -376,54 +394,59 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	echo sparc-icl-nx6
 	exit ;;
    DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
-	case `/usr/bin/uname -p` in
+	case $(/usr/bin/uname -p) in
 	    sparc) echo sparc-icl-nx7; exit ;;
 	esac ;;
    s390x:SunOS:*:*)
-	echo "$UNAME_MACHINE"-ibm-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	echo "$UNAME_MACHINE"-ibm-solaris2"$(echo "$UNAME_RELEASE" | sed -e 's/[^.]*//')"
 	exit ;;
    sun4H:SunOS:5.*:*)
-	echo sparc-hal-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo sparc-hal-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
    sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
-	echo sparc-sun-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	echo sparc-sun-solaris2"$(echo "$UNAME_RELEASE" | sed -e 's/[^.]*//')"
 	exit ;;
    i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
 	echo i386-pc-auroraux"$UNAME_RELEASE"
 	exit ;;
    i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
-	UNAME_REL="`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	set_cc_for_build
-	case `isainfo -b` in
+	SUN_ARCH=i386
-	    32)
+	# If there is a compiler, see if it is configured for 64-bit objects.
-		echo i386-pc-solaris2"$UNAME_REL"
+	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
-		;;
+	# This test works for both compilers.
-	    64)
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
-		echo x86_64-pc-solaris2"$UNAME_REL"
+	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
-		;;
+		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-	esac
+		grep IS_64BIT_ARCH >/dev/null
 	    then
 		SUN_ARCH=x86_64
 	    fi
 	fi
 	echo "$SUN_ARCH"-pc-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
    sun4*:SunOS:6*:*)
 	# According to config.sub, this is the proper way to canonicalize
 	# SunOS6.  Hard to guess exactly what SunOS6 will be like, but
 	# it's likely to be more like Solaris than SunOS4.
-	echo sparc-sun-solaris3"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo sparc-sun-solaris3"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
    sun4*:SunOS:*:*)
-	case "`/usr/bin/arch -k`" in
+	case "$(/usr/bin/arch -k)" in
 	    Series*|S4*)
-		UNAME_RELEASE=`uname -v`
+		UNAME_RELEASE=$(uname -v)
 		;;
 	esac
 	# Japanese Language versions have a version number like `4.1.3-JL'.
-	echo sparc-sun-sunos"`echo "$UNAME_RELEASE"|sed -e 's/-/_/'`"
+	echo sparc-sun-sunos"$(echo "$UNAME_RELEASE"|sed -e 's/-/_/')"
 	exit ;;
    sun3*:SunOS:*:*)
 	echo m68k-sun-sunos"$UNAME_RELEASE"
 	exit ;;
    sun*:*:4.2BSD:*)
-	UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
+	UNAME_RELEASE=$( (sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null)
 	test "x$UNAME_RELEASE" = x && UNAME_RELEASE=3
-	case "`/bin/arch`" in
+	case "$(/bin/arch)" in
 	    sun3)
 		echo m68k-sun-sunos"$UNAME_RELEASE"
 		;;
@ -503,8 +526,8 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	}
 EOF
 	$CC_FOR_BUILD -o "$dummy" "$dummy.c" &&
-	  dummyarg=`echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p'` &&
+	  dummyarg=$(echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p') &&
-	  SYSTEM_NAME=`"$dummy" "$dummyarg"` &&
+	  SYSTEM_NAME=$("$dummy" "$dummyarg") &&
 	    { echo "$SYSTEM_NAME"; exit; }
 	echo mips-mips-riscos"$UNAME_RELEASE"
 	exit ;;
@ -531,11 +554,11 @@ EOF
 	exit ;;
    AViiON:dgux:*:*)
 	# DG/UX returns AViiON for all architectures
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	UNAME_PROCESSOR=$(/usr/bin/uname -p)
-	if [ "$UNAME_PROCESSOR" = mc88100 ] || [ "$UNAME_PROCESSOR" = mc88110 ]
+	if test "$UNAME_PROCESSOR" = mc88100 || test "$UNAME_PROCESSOR" = mc88110
 	then
-	    if [ "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx ] || \
+	    if test "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx || \
-	       [ "$TARGET_BINARY_INTERFACE"x = x ]
+	       test "$TARGET_BINARY_INTERFACE"x = x
 	    then
 		echo m88k-dg-dgux"$UNAME_RELEASE"
 	    else
@ -559,17 +582,17 @@ EOF
 	echo m68k-tektronix-bsd
 	exit ;;
    *:IRIX*:*:*)
-	echo mips-sgi-irix"`echo "$UNAME_RELEASE"|sed -e 's/-/_/g'`"
+	echo mips-sgi-irix"$(echo "$UNAME_RELEASE"|sed -e 's/-/_/g')"
 	exit ;;
    ????????:AIX?:[12].1:2)   # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
 	echo romp-ibm-aix     # uname -m gives an 8 hex-code CPU id
-	exit ;;               # Note that: echo "'`uname -s`'" gives 'AIX '
+	exit ;;               # Note that: echo "'$(uname -s)'" gives 'AIX '
    i*86:AIX:*:*)
 	echo i386-ibm-aix
 	exit ;;
    ia64:AIX:*:*)
-	if [ -x /usr/bin/oslevel ] ; then
+	if test -x /usr/bin/oslevel ; then
-		IBM_REV=`/usr/bin/oslevel`
+		IBM_REV=$(/usr/bin/oslevel)
 	else
 		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
 	fi
@ -589,7 +612,7 @@ EOF
 			exit(0);
 			}
 EOF
-		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"`
+		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=$("$dummy")
 		then
 			echo "$SYSTEM_NAME"
 		else
@ -602,15 +625,15 @@ EOF
 	fi
 	exit ;;
    *:AIX:*:[4567])
-	IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
+	IBM_CPU_ID=$(/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }')
 	if /usr/sbin/lsattr -El "$IBM_CPU_ID" | grep ' POWER' >/dev/null 2>&1; then
 		IBM_ARCH=rs6000
 	else
 		IBM_ARCH=powerpc
 	fi
-	if [ -x /usr/bin/lslpp ] ; then
+	if test -x /usr/bin/lslpp ; then
-		IBM_REV=`/usr/bin/lslpp -Lqc bos.rte.libc |
+		IBM_REV=$(/usr/bin/lslpp -Lqc bos.rte.libc |
-			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/`
+			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/)
 	else
 		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
 	fi
@ -638,14 +661,14 @@ EOF
 	echo m68k-hp-bsd4.4
 	exit ;;
    9000/[34678]??:HP-UX:*:*)
-	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	HPUX_REV=$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//')
 	case "$UNAME_MACHINE" in
 	    9000/31?)            HP_ARCH=m68000 ;;
 	    9000/[34]??)         HP_ARCH=m68k ;;
 	    9000/[678][0-9][0-9])
-		if [ -x /usr/bin/getconf ]; then
+		if test -x /usr/bin/getconf; then
-		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
+		    sc_cpu_version=$(/usr/bin/getconf SC_CPU_VERSION 2>/dev/null)
-		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
+		    sc_kernel_bits=$(/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null)
 		    case "$sc_cpu_version" in
 		      523) HP_ARCH=hppa1.0 ;; # CPU_PA_RISC1_0
 		      528) HP_ARCH=hppa1.1 ;; # CPU_PA_RISC1_1
@ -657,7 +680,7 @@ EOF
 			esac ;;
 		    esac
 		fi
-		if [ "$HP_ARCH" = "" ]; then
+		if test "$HP_ARCH" = ""; then
 		    set_cc_for_build
 		    sed 's/^		//' << EOF > "$dummy.c"
@ -692,11 +715,11 @@ EOF
 		    exit (0);
 		}
 EOF
-		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=`"$dummy"`
+		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=$("$dummy")
 		    test -z "$HP_ARCH" && HP_ARCH=hppa
 		fi ;;
 	esac
-	if [ "$HP_ARCH" = hppa2.0w ]
+	if test "$HP_ARCH" = hppa2.0w
 	then
 	    set_cc_for_build
@ -720,7 +743,7 @@ EOF
 	echo "$HP_ARCH"-hp-hpux"$HPUX_REV"
 	exit ;;
    ia64:HP-UX:*:*)
-	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	HPUX_REV=$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//')
 	echo ia64-hp-hpux"$HPUX_REV"
 	exit ;;
    3050*:HI-UX:*:*)
@ -750,7 +773,7 @@ EOF
 	  exit (0);
 	}
 EOF
-	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"` &&
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=$("$dummy") &&
 		{ echo "$SYSTEM_NAME"; exit; }
 	echo unknown-hitachi-hiuxwe2
 	exit ;;
@ -770,7 +793,7 @@ EOF
 	echo hppa1.0-hp-osf
 	exit ;;
    i*86:OSF1:*:*)
-	if [ -x /usr/sbin/sysversion ] ; then
+	if test -x /usr/sbin/sysversion ; then
 	    echo "$UNAME_MACHINE"-unknown-osf1mk
 	else
 	    echo "$UNAME_MACHINE"-unknown-osf1
@ -819,14 +842,14 @@ EOF
 	echo craynv-cray-unicosmp"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
 	exit ;;
    F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
-	FUJITSU_PROC=`uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`
+	FUJITSU_PROC=$(uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz)
-	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_SYS=$(uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///')
-	FUJITSU_REL=`echo "$UNAME_RELEASE" | sed -e 's/ /_/'`
+	FUJITSU_REL=$(echo "$UNAME_RELEASE" | sed -e 's/ /_/')
 	echo "${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
 	exit ;;
    5000:UNIX_System_V:4.*:*)
-	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
+	FUJITSU_SYS=$(uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///')
-	FUJITSU_REL=`echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/'`
+	FUJITSU_REL=$(echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/')
 	echo "sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
 	exit ;;
    i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
@ -838,26 +861,26 @@ EOF
    *:BSD/OS:*:*)
 	echo "$UNAME_MACHINE"-unknown-bsdi"$UNAME_RELEASE"
 	exit ;;
-    arm*:FreeBSD:*:*)
+    arm:FreeBSD:*:*)
-	UNAME_PROCESSOR=`uname -p`
+	UNAME_PROCESSOR=$(uname -p)
 	set_cc_for_build
 	if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
 	    | grep -q __ARM_PCS_VFP
 	then
-	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`"-gnueabi
+	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"$(echo ${UNAME_RELEASE}|sed -e 's/[-(].*//')"-gnueabi
 	else
-	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`"-gnueabihf
+	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"$(echo ${UNAME_RELEASE}|sed -e 's/[-(].*//')"-gnueabihf
 	fi
 	exit ;;
    *:FreeBSD:*:*)
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	UNAME_PROCESSOR=$(/usr/bin/uname -p)
 	case "$UNAME_PROCESSOR" in
 	    amd64)
 		UNAME_PROCESSOR=x86_64 ;;
 	    i386)
 		UNAME_PROCESSOR=i586 ;;
 	esac
-	echo "$UNAME_PROCESSOR"-unknown-freebsd"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	echo "$UNAME_PROCESSOR"-unknown-freebsd"$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')"
 	exit ;;
    i*:CYGWIN*:*)
 	echo "$UNAME_MACHINE"-pc-cygwin
@ -890,18 +913,18 @@ EOF
 	echo "$UNAME_MACHINE"-pc-uwin
 	exit ;;
    amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
-	echo x86_64-unknown-cygwin
+	echo x86_64-pc-cygwin
 	exit ;;
    prep*:SunOS:5.*:*)
-	echo powerpcle-unknown-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo powerpcle-unknown-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
    *:GNU:*:*)
 	# the GNU system
-	echo "`echo "$UNAME_MACHINE"|sed -e 's,[-/].*$,,'`-unknown-$LIBC`echo "$UNAME_RELEASE"|sed -e 's,/.*$,,'`"
+	echo "$(echo "$UNAME_MACHINE"|sed -e 's,[-/].*$,,')-unknown-$LIBC$(echo "$UNAME_RELEASE"|sed -e 's,/.*$,,')"
 	exit ;;
    *:GNU/*:*:*)
 	# other systems with GNU libc and userland
-	echo "$UNAME_MACHINE-unknown-`echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]"``echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`-$LIBC"
+	echo "$UNAME_MACHINE-unknown-$(echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]")$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')-$LIBC"
 	exit ;;
    *:Minix:*:*)
 	echo "$UNAME_MACHINE"-unknown-minix
@ -914,7 +937,7 @@ EOF
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
    alpha:Linux:*:*)
-	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+	case $(sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' /proc/cpuinfo 2>/dev/null) in
 	  EV5)   UNAME_MACHINE=alphaev5 ;;
 	  EV56)  UNAME_MACHINE=alphaev56 ;;
 	  PCA56) UNAME_MACHINE=alphapca56 ;;
@ -981,22 +1004,50 @@ EOF
 	exit ;;
    mips:Linux:*:* | mips64:Linux:*:*)
 	set_cc_for_build
 	IS_GLIBC=0
 	test x"${LIBC}" = xgnu && IS_GLIBC=1
 	sed 's/^	//' << EOF > "$dummy.c"
 	#undef CPU
-	#undef ${UNAME_MACHINE}
+	#undef mips
-	#undef ${UNAME_MACHINE}el
+	#undef mipsel
 	#undef mips64
 	#undef mips64el
 	#if ${IS_GLIBC} && defined(_ABI64)
 	LIBCABI=gnuabi64
 	#else
 	#if ${IS_GLIBC} && defined(_ABIN32)
 	LIBCABI=gnuabin32
 	#else
 	LIBCABI=${LIBC}
 	#endif
 	#endif
 	#if ${IS_GLIBC} && defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
 	CPU=mipsisa64r6
 	#else
 	#if ${IS_GLIBC} && !defined(__mips64) && defined(__mips_isa_rev) && __mips_isa_rev>=6
 	CPU=mipsisa32r6
 	#else
 	#if defined(__mips64)
 	CPU=mips64
 	#else
 	CPU=mips
 	#endif
 	#endif
 	#endif
 	#if defined(__MIPSEL__) || defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL)
-	CPU=${UNAME_MACHINE}el
+	MIPS_ENDIAN=el
 	#else
 	#if defined(__MIPSEB__) || defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB)
-	CPU=${UNAME_MACHINE}
+	MIPS_ENDIAN=
 	#else
-	CPU=
+	MIPS_ENDIAN=
 	#endif
 	#endif
 EOF
-	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU'`"
+	eval "$($CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU\|^MIPS_ENDIAN\|^LIBCABI')"
-	test "x$CPU" != x && { echo "$CPU-unknown-linux-$LIBC"; exit; }
+	test "x$CPU" != x && { echo "$CPU${MIPS_ENDIAN}-unknown-linux-$LIBCABI"; exit; }
 	;;
    mips64el:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
@ -1015,7 +1066,7 @@ EOF
 	exit ;;
    parisc:Linux:*:* | hppa:Linux:*:*)
 	# Look for CPU level
-	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
+	case $(grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2) in
 	  PA7*) echo hppa1.1-unknown-linux-"$LIBC" ;;
 	  PA8*) echo hppa2.0-unknown-linux-"$LIBC" ;;
 	  *)    echo hppa-unknown-linux-"$LIBC" ;;
@ -1055,7 +1106,17 @@ EOF
 	echo "$UNAME_MACHINE"-dec-linux-"$LIBC"
 	exit ;;
    x86_64:Linux:*:*)
-	echo "$UNAME_MACHINE"-pc-linux-"$LIBC"
+	set_cc_for_build
 	LIBCABI=$LIBC
 	if test "$CC_FOR_BUILD" != no_compiler_found; then
 	    if (echo '#ifdef __ILP32__'; echo IS_X32; echo '#endif') | \
 		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
 		grep IS_X32 >/dev/null
 	    then
 		LIBCABI="$LIBC"x32
 	    fi
 	fi
 	echo "$UNAME_MACHINE"-pc-linux-"$LIBCABI"
 	exit ;;
    xtensa*:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
@ -1095,7 +1156,7 @@ EOF
 	echo "$UNAME_MACHINE"-pc-msdosdjgpp
 	exit ;;
    i*86:*:4.*:*)
-	UNAME_REL=`echo "$UNAME_RELEASE" | sed 's/\/MP$//'`
+	UNAME_REL=$(echo "$UNAME_RELEASE" | sed 's/\/MP$//')
 	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
 		echo "$UNAME_MACHINE"-univel-sysv"$UNAME_REL"
 	else
@ -1104,19 +1165,19 @@ EOF
 	exit ;;
    i*86:*:5:[678]*)
 	# UnixWare 7.x, OpenUNIX and OpenServer 6.
-	case `/bin/uname -X | grep "^Machine"` in
+	case $(/bin/uname -X | grep "^Machine") in
 	    *486*)	     UNAME_MACHINE=i486 ;;
 	    *Pentium)	     UNAME_MACHINE=i586 ;;
 	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
 	esac
-	echo "$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}{$UNAME_VERSION}"
+	echo "$UNAME_MACHINE-unknown-sysv${UNAME_RELEASE}${UNAME_SYSTEM}${UNAME_VERSION}"
 	exit ;;
    i*86:*:3.2:*)
 	if test -f /usr/options/cb.name; then
-		UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
+		UNAME_REL=$(sed -n 's/.*Version //p' </usr/options/cb.name)
 		echo "$UNAME_MACHINE"-pc-isc"$UNAME_REL"
 	elif /bin/uname -X 2>/dev/null >/dev/null ; then
-		UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
+		UNAME_REL=$( (/bin/uname -X|grep Release|sed -e 's/.*= //'))
 		(/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
 		(/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
 			&& UNAME_MACHINE=i586
@ -1166,7 +1227,7 @@ EOF
    3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
 	OS_REL=''
 	test -r /etc/.relid \
-	&& OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	&& OS_REL=.$(sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid)
 	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
 	  && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
 	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
@ -1177,7 +1238,7 @@ EOF
    NCR*:*:4.2:* | MPRAS*:*:4.2:*)
 	OS_REL='.3'
 	test -r /etc/.relid \
-	    && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	    && OS_REL=.$(sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid)
 	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
 	    && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
 	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
@ -1210,7 +1271,7 @@ EOF
 	exit ;;
    *:SINIX-*:*:*)
 	if uname -p 2>/dev/null >/dev/null ; then
-		UNAME_MACHINE=`(uname -p) 2>/dev/null`
+		UNAME_MACHINE=$( (uname -p) 2>/dev/null)
 		echo "$UNAME_MACHINE"-sni-sysv4
 	else
 		echo ns32k-sni-sysv
@ -1244,7 +1305,7 @@ EOF
 	echo mips-sony-newsos6
 	exit ;;
    R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
-	if [ -d /usr/nec ]; then
+	if test -d /usr/nec; then
 		echo mips-nec-sysv"$UNAME_RELEASE"
 	else
 		echo mips-unknown-sysv"$UNAME_RELEASE"
@ -1292,44 +1353,48 @@ EOF
    *:Rhapsody:*:*)
 	echo "$UNAME_MACHINE"-apple-rhapsody"$UNAME_RELEASE"
 	exit ;;
    arm64:Darwin:*:*)
 	echo aarch64-apple-darwin"$UNAME_RELEASE"
 	exit ;;
    *:Darwin:*:*)
-	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
+	UNAME_PROCESSOR=$(uname -p)
-	set_cc_for_build
+	case $UNAME_PROCESSOR in
-	if test "$UNAME_PROCESSOR" = unknown ; then
+	    unknown) UNAME_PROCESSOR=powerpc ;;
-	    UNAME_PROCESSOR=powerpc
+	esac
 	if command -v xcode-select > /dev/null 2> /dev/null && \
 		! xcode-select --print-path > /dev/null 2> /dev/null ; then
 	    # Avoid executing cc if there is no toolchain installed as
 	    # cc will be a stub that puts up a graphical alert
 	    # prompting the user to install developer tools.
 	    CC_FOR_BUILD=no_compiler_found
 	else
 	    set_cc_for_build
 	fi
-	if test "`echo "$UNAME_RELEASE" | sed -e 's/\..*//'`" -le 10 ; then
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
-	    if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	    if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
-		if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_64BIT_ARCH >/dev/null
-		       grep IS_64BIT_ARCH >/dev/null
+	    then
-		then
+		case $UNAME_PROCESSOR in
-		    case $UNAME_PROCESSOR in
+		    i386) UNAME_PROCESSOR=x86_64 ;;
-			i386) UNAME_PROCESSOR=x86_64 ;;
+		    powerpc) UNAME_PROCESSOR=powerpc64 ;;
-			powerpc) UNAME_PROCESSOR=powerpc64 ;;
+		esac
-		    esac
+	    fi
-		fi
+	    # On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
-		# On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+	    if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
-		if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_PPC >/dev/null
-		       grep IS_PPC >/dev/null
+	    then
-		then
+		UNAME_PROCESSOR=powerpc
 		    UNAME_PROCESSOR=powerpc
 		fi
 	    fi
 	elif test "$UNAME_PROCESSOR" = i386 ; then
-	    # Avoid executing cc on OS X 10.9, as it ships with a stub
+	    # uname -m returns i386 or x86_64
-	    # that puts up a graphical alert prompting to install
+	    UNAME_PROCESSOR=$UNAME_MACHINE
 	    # developer tools.  Any system running Mac OS X 10.7 or
 	    # later (Darwin 11 and later) is required to have a 64-bit
 	    # processor. This is not true of the ARM version of Darwin
 	    # that Apple uses in portable devices.
 	    UNAME_PROCESSOR=x86_64
 	fi
 	echo "$UNAME_PROCESSOR"-apple-darwin"$UNAME_RELEASE"
 	exit ;;
    *:procnto*:*:* | *:QNX:[0123456789]*:*)
-	UNAME_PROCESSOR=`uname -p`
+	UNAME_PROCESSOR=$(uname -p)
 	if test "$UNAME_PROCESSOR" = x86; then
 		UNAME_PROCESSOR=i386
 		UNAME_MACHINE=pc
@ -1397,10 +1462,10 @@ EOF
 	echo mips-sei-seiux"$UNAME_RELEASE"
 	exit ;;
    *:DragonFly:*:*)
-	echo "$UNAME_MACHINE"-unknown-dragonfly"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	echo "$UNAME_MACHINE"-unknown-dragonfly"$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')"
 	exit ;;
    *:*VMS:*:*)
-	UNAME_MACHINE=`(uname -p) 2>/dev/null`
+	UNAME_MACHINE=$( (uname -p) 2>/dev/null)
 	case "$UNAME_MACHINE" in
 	    A*) echo alpha-dec-vms ; exit ;;
 	    I*) echo ia64-dec-vms ; exit ;;
@ -1410,7 +1475,7 @@ EOF
 	echo i386-pc-xenix
 	exit ;;
    i*86:skyos:*:*)
-	echo "$UNAME_MACHINE"-pc-skyos"`echo "$UNAME_RELEASE" | sed -e 's/ .*$//'`"
+	echo "$UNAME_MACHINE"-pc-skyos"$(echo "$UNAME_RELEASE" | sed -e 's/ .*$//')"
 	exit ;;
    i*86:rdos:*:*)
 	echo "$UNAME_MACHINE"-pc-rdos
@ -1424,8 +1489,148 @@ EOF
    amd64:Isilon\ OneFS:*:*)
 	echo x86_64-unknown-onefs
 	exit ;;
    *:Unleashed:*:*)
 	echo "$UNAME_MACHINE"-unknown-unleashed"$UNAME_RELEASE"
 	exit ;;
 esac
 # No uname command or uname output not recognized.
 set_cc_for_build
 cat > "$dummy.c" <<EOF
 #ifdef _SEQUENT_
 #include <sys/types.h>
 #include <sys/utsname.h>
 #endif
 #if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
 #if defined (vax) || defined (__vax) || defined (__vax__) || defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
 #include <signal.h>
 #if defined(_SIZE_T_) || defined(SIGLOST)
 #include <sys/utsname.h>
 #endif
 #endif
 #endif
 main ()
 {
 #if defined (sony)
 #if defined (MIPSEB)
  /* BFD wants "bsd" instead of "newsos".  Perhaps BFD should be changed,
     I don't know....  */
  printf ("mips-sony-bsd\n"); exit (0);
 #else
 #include <sys/param.h>
  printf ("m68k-sony-newsos%s\n",
 #ifdef NEWSOS4
  "4"
 #else
  ""
 #endif
  ); exit (0);
 #endif
 #endif
 #if defined (NeXT)
 #if !defined (__ARCHITECTURE__)
 #define __ARCHITECTURE__ "m68k"
 #endif
  int version;
  version=$( (hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null);
  if (version < 4)
    printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
  else
    printf ("%s-next-openstep%d\n", __ARCHITECTURE__, version);
  exit (0);
 #endif
 #if defined (MULTIMAX) || defined (n16)
 #if defined (UMAXV)
  printf ("ns32k-encore-sysv\n"); exit (0);
 #else
 #if defined (CMU)
  printf ("ns32k-encore-mach\n"); exit (0);
 #else
  printf ("ns32k-encore-bsd\n"); exit (0);
 #endif
 #endif
 #endif
 #if defined (__386BSD__)
  printf ("i386-pc-bsd\n"); exit (0);
 #endif
 #if defined (sequent)
 #if defined (i386)
  printf ("i386-sequent-dynix\n"); exit (0);
 #endif
 #if defined (ns32000)
  printf ("ns32k-sequent-dynix\n"); exit (0);
 #endif
 #endif
 #if defined (_SEQUENT_)
  struct utsname un;
  uname(&un);
  if (strncmp(un.version, "V2", 2) == 0) {
    printf ("i386-sequent-ptx2\n"); exit (0);
  }
  if (strncmp(un.version, "V1", 2) == 0) { /* XXX is V1 correct? */
    printf ("i386-sequent-ptx1\n"); exit (0);
  }
  printf ("i386-sequent-ptx\n"); exit (0);
 #endif
 #if defined (vax)
 #if !defined (ultrix)
 #include <sys/param.h>
 #if defined (BSD)
 #if BSD == 43
  printf ("vax-dec-bsd4.3\n"); exit (0);
 #else
 #if BSD == 199006
  printf ("vax-dec-bsd4.3reno\n"); exit (0);
 #else
  printf ("vax-dec-bsd\n"); exit (0);
 #endif
 #endif
 #else
  printf ("vax-dec-bsd\n"); exit (0);
 #endif
 #else
 #if defined(_SIZE_T_) || defined(SIGLOST)
  struct utsname un;
  uname (&un);
  printf ("vax-dec-ultrix%s\n", un.release); exit (0);
 #else
  printf ("vax-dec-ultrix\n"); exit (0);
 #endif
 #endif
 #endif
 #if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
 #if defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
 #if defined(_SIZE_T_) || defined(SIGLOST)
  struct utsname *un;
  uname (&un);
  printf ("mips-dec-ultrix%s\n", un.release); exit (0);
 #else
  printf ("mips-dec-ultrix\n"); exit (0);
 #endif
 #endif
 #endif
 #if defined (alliant) && defined (i860)
  printf ("i860-alliant-bsd\n"); exit (0);
 #endif
  exit (1);
 }
 EOF
 $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null && SYSTEM_NAME=$($dummy) &&
 	{ echo "$SYSTEM_NAME"; exit; }
 # Apollos put the system type in the environment.
 test -d /usr/apollo && { echo "$ISP-apollo-$SYSTYPE"; exit; }
 echo "$0: unable to guess system type" >&2
 case "$UNAME_MACHINE:$UNAME_SYSTEM" in
@ -1445,9 +1650,15 @@ This script (version $timestamp), has failed to recognize the
 operating system you are using. If your script is old, overwrite *all*
 copies of config.guess and config.sub with the latest versions from:
-  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
 and
-  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.sub
 EOF
 year=$(echo $timestamp | sed 's,-.*,,')
 # shellcheck disable=SC2003
 if test "$(expr "$(date +%Y)" - "$year")" -lt 3 ; then
   cat >&2 <<EOF
 If $0 has already been updated, send the following data and any
 information you think might be pertinent to config-patches@gnu.org to
@ -1455,26 +1666,27 @@ provide the necessary information to handle your system.
 config.guess timestamp = $timestamp
-uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -m = $( (uname -m) 2>/dev/null || echo unknown)
-uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -r = $( (uname -r) 2>/dev/null || echo unknown)
-uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -s = $( (uname -s) 2>/dev/null || echo unknown)
-uname -v = `(uname -v) 2>/dev/null || echo unknown`
+uname -v = $( (uname -v) 2>/dev/null || echo unknown)
-/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
+/usr/bin/uname -p = $( (/usr/bin/uname -p) 2>/dev/null)
-/bin/uname -X     = `(/bin/uname -X) 2>/dev/null`
+/bin/uname -X     = $( (/bin/uname -X) 2>/dev/null)
-hostinfo               = `(hostinfo) 2>/dev/null`
+hostinfo               = $( (hostinfo) 2>/dev/null)
-/bin/universe          = `(/bin/universe) 2>/dev/null`
+/bin/universe          = $( (/bin/universe) 2>/dev/null)
-/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null`
+/usr/bin/arch -k       = $( (/usr/bin/arch -k) 2>/dev/null)
-/bin/arch              = `(/bin/arch) 2>/dev/null`
+/bin/arch              = $( (/bin/arch) 2>/dev/null)
-/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null`
+/usr/bin/oslevel       = $( (/usr/bin/oslevel) 2>/dev/null)
-/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
+/usr/convex/getsysinfo = $( (/usr/convex/getsysinfo) 2>/dev/null)
 UNAME_MACHINE = "$UNAME_MACHINE"
 UNAME_RELEASE = "$UNAME_RELEASE"
 UNAME_SYSTEM  = "$UNAME_SYSTEM"
 UNAME_VERSION = "$UNAME_VERSION"
 EOF
 fi
 exit 1
--- a/config/config.sub
+++ b/config/config.sub
--- a/configure.ac
+++ b/configure.ac
@ -1,4 +1,5 @@
-AC_INIT(nix, m4_esyscmd([bash -c "echo -n $(cat ./version)$VERSION_SUFFIX"]))
+AC_INIT(nix, m4_esyscmd([bash -c "echo -n $(cat ./.version)$VERSION_SUFFIX"]))
 AC_CONFIG_MACRO_DIRS([m4])
 AC_CONFIG_SRCDIR(README.md)
 AC_CONFIG_AUX_DIR(config)
@ -42,13 +43,25 @@ esac
 AC_MSG_RESULT($system)
 AC_SUBST(system)
-AC_DEFINE_UNQUOTED(SYSTEM, ["$system"], [platform identifier (`cpu-os')])
+AC_DEFINE_UNQUOTED(SYSTEM, ["$system"], [platform identifier ('cpu-os')])
 # State should be stored in /nix/var, unless the user overrides it explicitly.
 test "$localstatedir" = '${prefix}/var' && localstatedir=/nix/var
 CFLAGS=
 CXXFLAGS=
 AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_CPP
 AC_CHECK_TOOL([AR], [ar])
 # Use 64-bit file system calls so that we can support files > 2 GiB.
 AC_SYS_LARGEFILE
 # Solaris-specific stuff.
 AC_STRUCT_DIRENT_D_TYPE
 if test "$sys_name" = sunos; then
@ -57,18 +70,6 @@ if test "$sys_name" = sunos; then
 fi
 CFLAGS=
 CXXFLAGS=
 AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_CPP
 AX_CXX_COMPILE_STDCXX_14
 # Use 64-bit file system calls so that we can support files > 2 GiB.
 AC_SYS_LARGEFILE
 # Check for pubsetbuf.
 AC_MSG_CHECKING([for pubsetbuf])
 AC_LANG_PUSH(C++)
@ -116,26 +117,14 @@ fi
 ])
 NEED_PROG(bash, bash)
 NEED_PROG(patch, patch)
 AC_PATH_PROG(xmllint, xmllint, false)
 AC_PATH_PROG(xsltproc, xsltproc, false)
 AC_PATH_PROG(flex, flex, false)
 AC_PATH_PROG(bison, bison, false)
 NEED_PROG(sed, sed)
 NEED_PROG(tar, tar)
 NEED_PROG(bzip2, bzip2)
 NEED_PROG(gzip, gzip)
 NEED_PROG(xz, xz)
 AC_PATH_PROG(dot, dot)
 AC_PATH_PROG(lsof, lsof, lsof)
 NEED_PROG(jq, jq)
-NEED_PROG(cat, cat)
+AC_SUBST(coreutils, [$(dirname $(type -p cat))])
 NEED_PROG(tr, tr)
 AC_ARG_WITH(coreutils-bin, AC_HELP_STRING([--with-coreutils-bin=PATH],
  [path of cat, mkdir, etc.]),
  coreutils=$withval, coreutils=$(dirname $cat))
 AC_SUBST(coreutils)
 AC_ARG_WITH(store-dir, AC_HELP_STRING([--with-store-dir=PATH],
@ -144,40 +133,87 @@ AC_ARG_WITH(store-dir, AC_HELP_STRING([--with-store-dir=PATH],
 AC_SUBST(storedir)
-# Look for OpenSSL, a required dependency.
+# Look for boost, a required dependency.
 # Note that AX_BOOST_BASE only exports *CPP* BOOST_CPPFLAGS, no CXX flags,
 # and CPPFLAGS are not passed to the C++ compiler automatically.
 # Thus we append the returned CPPFLAGS to the CXXFLAGS here.
 AX_BOOST_BASE([1.66], [CXXFLAGS="$BOOST_CPPFLAGS $CXXFLAGS"], [AC_MSG_ERROR([Nix requires boost.])])
 # For unknown reasons, setting this directly in the ACTION-IF-FOUND above
 # ends up with LDFLAGS being empty, so we set it afterwards.
 LDFLAGS="$BOOST_LDFLAGS $LDFLAGS"
 # On some platforms, new-style atomics need a helper library
 AC_MSG_CHECKING(whether -latomic is needed)
 AC_LINK_IFELSE([AC_LANG_SOURCE([[
 #include <stdint.h>
 uint64_t v;
 int main() {
    return (int)__atomic_load_n(&v, __ATOMIC_ACQUIRE);
 }]])], GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=no, GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=yes)
 AC_MSG_RESULT($GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC)
 if test "x$GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC" = xyes; then
    LIBS="-latomic $LIBS"
 fi
 PKG_PROG_PKG_CONFIG
 AC_ARG_ENABLE(shared, AC_HELP_STRING([--enable-shared],
  [Build shared libraries for Nix [default=yes]]),
  shared=$enableval, shared=yes)
 if test "$shared" = yes; then
  AC_SUBST(BUILD_SHARED_LIBS, 1, [Whether to build shared libraries.])
 else
  AC_SUBST(BUILD_SHARED_LIBS, 0, [Whether to build shared libraries.])
  PKG_CONFIG="$PKG_CONFIG --static"
 fi
 # Look for OpenSSL, a required dependency. FIXME: this is only (maybe)
 # used by S3BinaryCacheStore.
 PKG_CHECK_MODULES([OPENSSL], [libcrypto], [CXXFLAGS="$OPENSSL_CFLAGS $CXXFLAGS"])
 # Look for libbz2, a required dependency.
 AC_CHECK_LIB([bz2], [BZ2_bzWriteOpen], [true],
-  [AC_MSG_ERROR([Nix requires libbz2, which is part of bzip2.  See https://web.archive.org/web/20180624184756/http://www.bzip.org/.])])
+  [AC_MSG_ERROR([Nix requires libbz2, which is part of bzip2.  See https://sourceware.org/bzip2/.])])
 AC_CHECK_HEADERS([bzlib.h], [true],
-  [AC_MSG_ERROR([Nix requires libbz2, which is part of bzip2.  See https://web.archive.org/web/20180624184756/http://www.bzip.org/.])])
+  [AC_MSG_ERROR([Nix requires libbz2, which is part of bzip2.  See https://sourceware.org/bzip2/.])])
-
+# Checks for libarchive
 PKG_CHECK_MODULES([LIBARCHIVE], [libarchive >= 3.1.2], [CXXFLAGS="$LIBARCHIVE_CFLAGS $CXXFLAGS"])
 # Workaround until https://github.com/libarchive/libarchive/issues/1446 is fixed
 if test "$shared" != yes; then
    LIBARCHIVE_LIBS+=' -lz'
 fi
 # Look for SQLite, a required dependency.
 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 $CXXFLAGS"])
 # Look for editline, a required dependency.
-PKG_CHECK_MODULES([EDITLINE], [libeditline], [CXXFLAGS="$EDITLINE_CFLAGS $CXXFLAGS"])
+# The the libeditline.pc file was added only in libeditline >= 1.15.2,
 # see https://github.com/troglobit/editline/commit/0a8f2ef4203c3a4a4726b9dd1336869cd0da8607,
 # but e.g. Ubuntu 16.04 has an older version, so we fall back to searching for
 # editline.h when the pkg-config approach fails.
 PKG_CHECK_MODULES([EDITLINE], [libeditline], [CXXFLAGS="$EDITLINE_CFLAGS $CXXFLAGS"], [
  AC_CHECK_HEADERS([editline.h], [true],
    [AC_MSG_ERROR([Nix requires libeditline; it was found neither via pkg-config nor its normal header.])])
  AC_SEARCH_LIBS([readline read_history], [editline], [],
    [AC_MSG_ERROR([Nix requires libeditline; it was not found via pkg-config, but via its header, but required functions do not work. Maybe it is too old? >= 1.14 is required.])])
 ])
 # Look for libsodium, an optional dependency.
-PKG_CHECK_MODULES([SODIUM], [libsodium],
+PKG_CHECK_MODULES([SODIUM], [libsodium], [CXXFLAGS="$SODIUM_CFLAGS $CXXFLAGS"])
  [AC_DEFINE([HAVE_SODIUM], [1], [Whether to use libsodium for cryptography.])
   CXXFLAGS="$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 $CXXFLAGS"])
 AC_CHECK_LIB([lzma], [lzma_stream_encoder_mt],
  [AC_DEFINE([HAVE_LZMA_MT], [1], [xz multithreaded compression support])])
 # Look for zlib, a required dependency.
 PKG_CHECK_MODULES([ZLIB], [zlib], [CXXFLAGS="$ZLIB_CFLAGS $CXXFLAGS"])
 AC_CHECK_HEADER([zlib.h],[:],[AC_MSG_ERROR([could not find the zlib.h header])])
 LDFLAGS="-lz $LDFLAGS"
 # Look for libbrotli{enc,dec}.
 PKG_CHECK_MODULES([LIBBROTLI], [libbrotlienc libbrotlidec], [CXXFLAGS="$LIBBROTLI_CFLAGS $CXXFLAGS"])
@ -215,13 +251,14 @@ if test -n "$enable_s3"; then
  declare -a aws_version_tokens=($(printf '#include <aws/core/VersionConfig.h>\nAWS_SDK_VERSION_STRING' | $CPP $CPPFLAGS - | grep -v '^#.*' | sed 's/"//g' | tr '.' ' '))
  AC_DEFINE_UNQUOTED([AWS_VERSION_MAJOR], ${aws_version_tokens@<:@0@:>@}, [Major version of aws-sdk-cpp.])
  AC_DEFINE_UNQUOTED([AWS_VERSION_MINOR], ${aws_version_tokens@<:@1@:>@}, [Minor version of aws-sdk-cpp.])
  AC_DEFINE_UNQUOTED([AWS_VERSION_PATCH], ${aws_version_tokens@<:@2@:>@}, [Patch version of aws-sdk-cpp.])
 fi
 # Whether to use the Boehm garbage collector.
 AC_ARG_ENABLE(gc, AC_HELP_STRING([--enable-gc],
-  [enable garbage collection in the Nix expression evaluator (requires Boehm GC) [default=no]]),
+  [enable garbage collection in the Nix expression evaluator (requires Boehm GC) [default=yes]]),
-  gc=$enableval, gc=no)
+  gc=$enableval, gc=yes)
 if test "$gc" = yes; then
  PKG_CHECK_MODULES([BDW_GC], [bdw-gc])
  CXXFLAGS="$BDW_GC_CFLAGS $CXXFLAGS"
@ -229,6 +266,10 @@ if test "$gc" = yes; then
 fi
 # Look for gtest.
 PKG_CHECK_MODULES([GTEST], [gtest_main])
 # documentation generation switch
 AC_ARG_ENABLE(doc-gen, AC_HELP_STRING([--disable-doc-gen],
  [disable documentation generation]),
@ -267,7 +308,6 @@ AC_ARG_WITH(sandbox-shell, AC_HELP_STRING([--with-sandbox-shell=PATH],
  sandbox_shell=$withval)
 AC_SUBST(sandbox_shell)
 # Expand all variables in config.status.
 test "$prefix" = NONE && prefix=$ac_default_prefix
 test "$exec_prefix" = NONE && exec_prefix='${prefix}'
--- a/contrib/stack-collapse.py
+++ b/contrib/stack-collapse.py
@ -0,0 +1,38 @@
 #!/usr/bin/env nix-shell
 #!nix-shell -i python3 -p python3 --pure
 # To be used with `--trace-function-calls` and `flamegraph.pl`.
 #
 # For example:
 #
 # nix-instantiate --trace-function-calls '<nixpkgs>' -A hello 2> nix-function-calls.trace
 # ./contrib/stack-collapse.py nix-function-calls.trace > nix-function-calls.folded
 # nix-shell -p flamegraph --run "flamegraph.pl nix-function-calls.folded > nix-function-calls.svg"
 import sys
 from pprint import pprint
 import fileinput
 stack = []
 timestack = []
 for line in fileinput.input():
    components = line.strip().split(" ", 2)
    if components[0] != "function-trace":
        continue
    direction = components[1]
    components = components[2].rsplit(" ", 2)
    loc = components[0]
    _at = components[1]
    time = int(components[2])
    if direction == "entered":
        stack.append(loc)
        timestack.append(time)
    elif direction == "exited":
        dur = time - timestack.pop()
        vst = ";".join(stack)
        print(f"{vst} {dur}")
        stack.pop()
--- a/corepkgs/config.nix.in
+++ b/corepkgs/config.nix.in
@ -1,29 +0,0 @@
 let
  fromEnv = var: def:
    let val = builtins.getEnv var; in
    if val != "" then val else def;
 in rec {
  shell = "@bash@";
  coreutils = "@coreutils@";
  bzip2 = "@bzip2@";
  gzip = "@gzip@";
  xz = "@xz@";
  tar = "@tar@";
  tarFlags = "@tarFlags@";
  tr = "@tr@";
  nixBinDir = fromEnv "NIX_BIN_DIR" "@bindir@";
  nixPrefix = "@prefix@";
  nixLibexecDir = fromEnv "NIX_LIBEXEC_DIR" "@libexecdir@";
  nixLocalstateDir = "@localstatedir@";
  nixSysconfDir = "@sysconfdir@";
  nixStoreDir = fromEnv "NIX_STORE_DIR" "@storedir@";
  # 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
      [ ];
 }
--- a/corepkgs/local.mk
+++ b/corepkgs/local.mk
@ -1,5 +0,0 @@
 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)))
 template-files += $(d)/config.nix
--- a/corepkgs/unpack-channel.nix
+++ b/corepkgs/unpack-channel.nix
@ -1,43 +0,0 @@
 with import <nix/config.nix>;
 let
  builder = builtins.toFile "unpack-channel.sh"
    ''
      mkdir $out
      cd $out
      xzpat="\.xz\$"
      gzpat="\.gz\$"
      if [[ "$src" =~ $xzpat ]]; then
        ${xz} -d < $src | ${tar} xf - ${tarFlags}
      elif [[ "$src" =~ $gzpat ]]; then
        ${gzip} -d < $src | ${tar} xf - ${tarFlags}
      else
        ${bzip2} -d < $src | ${tar} xf - ${tarFlags}
      fi
      if [ * != $channelName ]; then
        mv * $out/$channelName
      fi
      if [ -n "$binaryCacheURL" ]; then
        mkdir $out/binary-caches
        echo -n "$binaryCacheURL" > $out/binary-caches/$channelName
      fi
    '';
 in
 { name, channelName, src, binaryCacheURL ? "" }:
 derivation {
  system = builtins.currentSystem;
  builder = shell;
  args = [ "-e" builder ];
  inherit name channelName src binaryCacheURL;
  PATH = "${nixBinDir}:${coreutils}";
  # No point in doing this remotely.
  preferLocalBuild = true;
  inherit chrootDeps;
 }
--- a/default.nix
+++ b/default.nix
@ -0,0 +1,3 @@
 (import (fetchTarball https://github.com/edolstra/flake-compat/archive/master.tar.gz) {
  src = ./.;
 }).defaultNix
--- a/doc/manual/advanced-topics/advanced-topics.xml
+++ b/doc/manual/advanced-topics/advanced-topics.xml
@ -1,11 +0,0 @@
 <part xmlns="http://docbook.org/ns/docbook"
      xmlns:xlink="http://www.w3.org/1999/xlink"
      xmlns:xi="http://www.w3.org/2001/XInclude"
      xml:id="part-advanced-topics"
      version="5.0">
 <title>Advanced Topics</title>
 <xi:include href="distributed-builds.xml" />
 </part>
--- a/doc/manual/advanced-topics/distributed-builds.xml
+++ b/doc/manual/advanced-topics/distributed-builds.xml
@ -1,183 +0,0 @@
 <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='chap-distributed-builds'>
 <title>Remote Builds</title>
 <para>Nix supports remote builds, where a local Nix installation can
 forward Nix builds to other machines.  This allows multiple builds to
 be performed in parallel and allows Nix to perform multi-platform
 builds in a semi-transparent way.  For instance, if you perform a
 build for a <literal>x86_64-darwin</literal> on an
 <literal>i686-linux</literal> machine, Nix can automatically forward
 the build to a <literal>x86_64-darwin</literal> machine, if
 available.</para>
 <para>To forward a build to a remote machine, it’s required that the
 remote machine is accessible via SSH and that it has Nix
 installed. You can test whether connecting to the remote Nix instance
 works, e.g.
 <screen>
 $ nix ping-store --store ssh://mac
 </screen>
 will try to connect to the machine named <literal>mac</literal>. It is
 possible to specify an SSH identity file as part of the remote store
 URI, e.g.
 <screen>
 $ nix ping-store --store ssh://mac?ssh-key=/home/alice/my-key
 </screen>
 Since builds should be non-interactive, the key should not have a
 passphrase. Alternatively, you can load identities ahead of time into
 <command>ssh-agent</command> or <command>gpg-agent</command>.</para>
 <para>If you get the error
 <screen>
 bash: nix-store: command not found
 error: cannot connect to 'mac'
 </screen>
 then you need to ensure that the <envar>PATH</envar> of
 non-interactive login shells contains Nix.</para>
 <warning><para>If you are building via the Nix daemon, it is the Nix
 daemon user account (that is, <literal>root</literal>) that should
 have SSH access to the remote machine. If you can’t or don’t want to
 configure <literal>root</literal> to be able to access to remote
 machine, you can use a private Nix store instead by passing
 e.g. <literal>--store ~/my-nix</literal>.</para></warning>
 <para>The list of remote machines can be specified on the command line
 or in the Nix configuration file. The former is convenient for
 testing. For example, the following command allows you to build a
 derivation for <literal>x86_64-darwin</literal> on a Linux machine:
 <screen>
 $ uname
 Linux
 $ nix build \
  '(with import &lt;nixpkgs> { system = "x86_64-darwin"; }; runCommand "foo" {} "uname > $out")' \
  --builders 'ssh://mac x86_64-darwin'
 [1/0/1 built, 0.0 MiB DL] building foo on ssh://mac
 $ cat ./result
 Darwin
 </screen>
 It is possible to specify multiple builders separated by a semicolon
 or a newline, e.g.
 <screen>
  --builders 'ssh://mac x86_64-darwin ; ssh://beastie x86_64-freebsd'
 </screen>
 </para>
 <para>Each machine specification consists of the following elements,
 separated by spaces. Only the first element is required.
 To leave a field at its default, set it to <literal>-</literal>.
 <orderedlist>
  <listitem><para>The URI of the remote store in the format
  <literal>ssh://[<replaceable>username</replaceable>@]<replaceable>hostname</replaceable></literal>,
  e.g. <literal>ssh://nix@mac</literal> or
  <literal>ssh://mac</literal>. For backward compatibility,
  <literal>ssh://</literal> may be omitted. The hostname may be an
  alias defined in your
  <filename>~/.ssh/config</filename>.</para></listitem>
  <listitem><para>A comma-separated list of Nix platform type
  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>. If omitted, this
  defaults to the local platform type.</para></listitem>
  <listitem><para>The SSH identity file to be used to log in to the
  remote machine. If omitted, SSH will use its regular
  identities.</para></listitem>
  <listitem><para>The maximum number of builds that Nix will execute
  in parallel on the machine.  Typically this should be equal to the
  number of CPU cores.  For instance, the machine
  <literal>itchy</literal> in the example will execute up to 8 builds
  in parallel.</para></listitem>
  <listitem><para>The “speed factor”, indicating the relative speed of
  the machine.  If there are multiple machines of the right type, Nix
  will prefer the fastest, taking load into account.</para></listitem>
  <listitem><para>A comma-separated list of <emphasis>supported
  features</emphasis>.  If a derivation has the
  <varname>requiredSystemFeatures</varname> attribute, then Nix will
  only perform the derivation on a machine that has the specified
  features.  For instance, the attribute
 <programlisting>
 requiredSystemFeatures = [ "kvm" ];
 </programlisting>
  will cause the build to be performed on a machine that has the
  <literal>kvm</literal> feature.</para></listitem>
  <listitem><para>A comma-separated list of <emphasis>mandatory
  features</emphasis>.  A machine will only be used to build a
  derivation if all of the machine’s mandatory features appear in the
  derivation’s <varname>requiredSystemFeatures</varname>
  attribute..</para></listitem>
 </orderedlist>
 For example, the machine specification
 <programlisting>
 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        1 2 kvm benchmark
 </programlisting>
 specifies several machines that can perform
 <literal>i686-linux</literal> builds. However,
 <literal>poochie</literal> will only do builds that have the attribute
 <programlisting>
 requiredSystemFeatures = [ "benchmark" ];
 </programlisting>
 or
 <programlisting>
 requiredSystemFeatures = [ "benchmark" "kvm" ];
 </programlisting>
 <literal>itchy</literal> cannot do builds that require
 <literal>kvm</literal>, but <literal>scratchy</literal> does support
 such builds. For regular builds, <literal>itchy</literal> will be
 preferred over <literal>scratchy</literal> because it has a higher
 speed factor.</para>
 <para>Remote builders can also be configured in
 <filename>nix.conf</filename>, e.g.
 <programlisting>
 builders = ssh://mac x86_64-darwin ; ssh://beastie x86_64-freebsd
 </programlisting>
 Finally, remote builders can be configured in a separate configuration
 file included in <option>builders</option> via the syntax
 <literal>@<replaceable>file</replaceable></literal>. For example,
 <programlisting>
 builders = @/etc/nix/machines
 </programlisting>
 causes the list of machines in <filename>/etc/nix/machines</filename>
 to be included. (This is the default.)</para>
 </chapter>
--- a/doc/manual/book.toml
+++ b/doc/manual/book.toml
@ -0,0 +1,2 @@
 [output.html]
 additional-css = ["custom.css"]
--- a/doc/manual/command-ref/command-ref.xml
+++ b/doc/manual/command-ref/command-ref.xml
@ -1,20 +0,0 @@
 <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>
--- a/doc/manual/command-ref/conf-file.xml
+++ b/doc/manual/command-ref/conf-file.xml
--- a/doc/manual/command-ref/env-common.xml
+++ b/doc/manual/command-ref/env-common.xml
@ -1,196 +0,0 @@
 <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>
 <para>Most Nix commands interpret the following environment variables:</para>
 <variablelist xml:id="env-common">
 <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>
    <para>A colon-separated list of directories used to look up Nix
    expressions enclosed in angle brackets (i.e.,
    <literal>&lt;<replaceable>path</replaceable>></literal>).  For
    instance, the value
    <screen>
 /home/eelco/Dev:/etc/nixos</screen>
    will cause Nix to look for paths relative to
    <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>
    will cause Nix to search for
    <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>
    <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>
  <listitem>
  <para>Normally, the Nix store directory (typically
  <filename>/nix/store</filename>) is not allowed to contain any
  symlink components.  This is to prevent “impure” builds.  Builders
  sometimes “canonicalise” paths by resolving all symlink components.
  Thus, builds on different machines (with
  <filename>/nix/store</filename> resolving to different locations)
  could yield different results.  This is generally not a problem,
  except when builds are deployed to machines where
  <filename>/nix/store</filename> resolves differently.  If you are
  sure that you’re not going to do that, you can set
  <envar>NIX_IGNORE_SYMLINK_STORE</envar> to <envar>1</envar>.</para>
  <para>Note that if you’re symlinking the Nix store so that you can
  put it on another file system than the root file system, on Linux
  you’re better off using <literal>bind</literal> mount points, e.g.,
  <screen>
 $ mkdir /nix
 $ mount -o bind /mnt/otherdisk/nix /nix</screen>
  Consult the <citerefentry><refentrytitle>mount</refentrytitle>
  <manvolnum>8</manvolnum></citerefentry> manual page for details.</para>
  </listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_STORE_DIR</envar></term>
  <listitem><para>Overrides the location of the Nix store (default
  <filename><replaceable>prefix</replaceable>/store</filename>).</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_DATA_DIR</envar></term>
  <listitem><para>Overrides the location of the Nix static data
  directory (default
  <filename><replaceable>prefix</replaceable>/share</filename>).</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_LOG_DIR</envar></term>
  <listitem><para>Overrides the location of the Nix log directory
  (default <filename><replaceable>prefix</replaceable>/log/nix</filename>).</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_STATE_DIR</envar></term>
  <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_CONF_DIR</envar></term>
  <listitem><para>Overrides the location of the Nix configuration
  directory (default
  <filename><replaceable>prefix</replaceable>/etc/nix</filename>).</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>TMPDIR</envar></term>
  <listitem><para>Use the specified directory to store temporary
  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>
 <varlistentry xml:id="envar-remote"><term><envar>NIX_REMOTE</envar></term>
  <listitem><para>This variable should be set to
  <literal>daemon</literal> if you want to use the Nix daemon to
  execute Nix operations. This is necessary in <link
  linkend="ssec-multi-user">multi-user Nix installations</link>.
  If the Nix daemon's Unix socket is at some non-standard path,
  this variable should be set to <literal>unix://path/to/socket</literal>.
  Otherwise, it should be left unset.</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_SHOW_STATS</envar></term>
  <listitem><para>If set to <literal>1</literal>, Nix will print some
  evaluation statistics, such as the number of values
  allocated.</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>NIX_COUNT_CALLS</envar></term>
  <listitem><para>If set to <literal>1</literal>, Nix will print how
  often functions were called during Nix expression evaluation.  This
  is useful for profiling your Nix expressions.</para></listitem>
 </varlistentry>
 <varlistentry><term><envar>GC_INITIAL_HEAP_SIZE</envar></term>
  <listitem><para>If Nix has been configured to use the Boehm garbage
  collector, this variable sets the initial size of the heap in bytes.
  It defaults to 384 MiB.  Setting it to a low value reduces memory
  consumption, but will increase runtime due to the overhead of
  garbage collection.</para></listitem>
 </varlistentry>
 </variablelist>
 </chapter>
--- a/doc/manual/command-ref/files.xml
+++ b/doc/manual/command-ref/files.xml
@ -1,14 +0,0 @@
 <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>
--- a/doc/manual/command-ref/main-commands.xml
+++ b/doc/manual/command-ref/main-commands.xml
@ -1,17 +0,0 @@
 <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>
--- a/doc/manual/command-ref/nix-build.xml
+++ b/doc/manual/command-ref/nix-build.xml
@ -1,185 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-build</refname>
  <refpurpose>build a Nix expression</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-build</command>
    <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="opt-common-syn.xml#xmlns(db=http://docbook.org/ns/docbook)xpointer(/db:nop/*)" />
    <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>--no-out-link</option></arg>
    <arg>
      <group choice='req'>
        <arg choice='plain'><option>--out-link</option></arg>
        <arg choice='plain'><option>-o</option></arg>
      </group>
      <replaceable>outlink</replaceable>
    </arg>
    <arg choice='plain' rep='repeat'><replaceable>paths</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The <command>nix-build</command> command builds the derivations
 described by the Nix expressions in <replaceable>paths</replaceable>.
 If the build succeeds, it places a symlink to the result in the
 current directory.  The symlink is called <filename>result</filename>.
 If there are multiple Nix expressions, or the Nix expressions evaluate
 to multiple derivations, multiple sequentially numbered symlinks are
 created (<filename>result</filename>, <filename>result-2</filename>,
 and so on).</para>
 <para>If no <replaceable>paths</replaceable> are specified, then
 <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>
 (to translate a high-level Nix expression to a low-level store
 derivation) and <link
 linkend="rsec-nix-store-realise"><command>nix-store
 --realise</command></link> (to build the store derivation).</para>
 <warning><para>The result of the build is automatically registered as
 a root of the Nix garbage collector.  This root disappears
 automatically when the <filename>result</filename> symlink is deleted
 or renamed.  So don’t rename the symlink.</para></warning>
 </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>--no-out-link</option></term>
    <listitem><para>Do not create a symlink to the output path.  Note
    that as a result the output does not become a root of the garbage
    collector, and so might be deleted by <command>nix-store
    --gc</command>.</para></listitem>
  </varlistentry>
  <varlistentry xml:id='opt-out-link'><term><option>--out-link</option> /
  <option>-o</option> <replaceable>outlink</replaceable></term>
    <listitem><para>Change the name of the symlink to the output path
    created from <filename>result</filename> to
    <replaceable>outlink</replaceable>.</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>
 <screen>
 $ nix-build '&lt;nixpkgs>' -A firefox
 store derivation is /nix/store/qybprl8sz2lc...-firefox-1.5.0.7.drv
 /nix/store/d18hyl92g30l...-firefox-1.5.0.7
 $ ls -l result
 lrwxrwxrwx  <replaceable>...</replaceable>  result -> /nix/store/d18hyl92g30l...-firefox-1.5.0.7
 $ ls ./result/bin/
 firefox  firefox-config</screen>
 <para>If a derivation has multiple outputs,
 <command>nix-build</command> will build the default (first) output.
 You can also build all outputs:
 <screen>
 $ nix-build '&lt;nixpkgs>' -A openssl.all
 </screen>
 This will create a symlink for each output named
 <filename>result-<replaceable>outputname</replaceable></filename>.
 The suffix is omitted if the output name is <literal>out</literal>.
 So if <literal>openssl</literal> has outputs <literal>out</literal>,
 <literal>bin</literal> and <literal>man</literal>,
 <command>nix-build</command> will create symlinks
 <literal>result</literal>, <literal>result-bin</literal> and
 <literal>result-man</literal>.  It’s also possible to build a specific
 output:
 <screen>
 $ nix-build '&lt;nixpkgs>' -A openssl.man
 </screen>
 This will create a symlink <literal>result-man</literal>.</para>
 <para>Build a Nix expression given on the command line:
 <screen>
 $ nix-build -E 'with import &lt;nixpkgs> { }; runCommand "foo" { } "echo bar > $out"'
 $ cat ./result
 bar
 </screen>
 </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>
 <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>
--- a/doc/manual/command-ref/nix-channel.xml
+++ b/doc/manual/command-ref/nix-channel.xml
@ -1,191 +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"
      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 a 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 the
    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>
--- a/doc/manual/command-ref/nix-collect-garbage.xml
+++ b/doc/manual/command-ref/nix-collect-garbage.xml
@ -1,63 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-collect-garbage</refname>
  <refpurpose>delete unreachable store paths</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-collect-garbage</command>
    <arg><option>--delete-old</option></arg>
    <arg><option>-d</option></arg>
    <arg><option>--delete-older-than</option> <replaceable>period</replaceable></arg>
    <arg><option>--max-freed</option> <replaceable>bytes</replaceable></arg>
    <arg><option>--dry-run</option></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The command <command>nix-collect-garbage</command> is mostly an
 alias of <link linkend="rsec-nix-store-gc"><command>nix-store
 --gc</command></link>, that is, it deletes all unreachable paths in
 the Nix store to clean up your system.  However, it provides two
 additional options: <option>-d</option> (<option>--delete-old</option>),
 which deletes all old generations of all profiles in
 <filename>/nix/var/nix/profiles</filename> by invoking
 <literal>nix-env --delete-generations old</literal> on all profiles
 (of course, this makes rollbacks to previous configurations
 impossible); and
 <option>--delete-older-than</option> <replaceable>period</replaceable>,
 where period is a value such as <literal>30d</literal>, which deletes
 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>
 <refsection><title>Example</title>
 <para>To delete from the Nix store everything that is not used by the
 current generations of each profile, do
 <screen>
 $ nix-collect-garbage -d</screen>
 </para>
 </refsection>
 </refentry>
--- a/doc/manual/command-ref/nix-copy-closure.xml
+++ b/doc/manual/command-ref/nix-copy-closure.xml
@ -1,169 +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-copy-closure">
 <refmeta>
  <refentrytitle>nix-copy-closure</refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo class="source">Nix</refmiscinfo>
  <refmiscinfo class="version"><xi:include href="../version.txt" parse="text"/></refmiscinfo>
 </refmeta>
 <refnamediv>
  <refname>nix-copy-closure</refname>
  <refpurpose>copy a closure to or from a remote machine via SSH</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-copy-closure</command>
    <group>
      <arg choice='plain'><option>--to</option></arg>
      <arg choice='plain'><option>--from</option></arg>
    </group>
    <arg><option>--gzip</option></arg>
    <!--
    <arg><option>- -show-progress</option></arg>
    -->
    <arg><option>--include-outputs</option></arg>
    <group>
      <arg choice='plain'><option>--use-substitutes</option></arg>
      <arg choice='plain'><option>-s</option></arg>
    </group>
    <arg><option>-v</option></arg>
    <arg choice='plain'>
      <replaceable>user@</replaceable><replaceable>machine</replaceable>
    </arg>
    <arg choice='plain'><replaceable>paths</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para><command>nix-copy-closure</command> gives you an easy and
 efficient way to exchange software between machines.  Given one or
 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
 <command>ssh</command> (Secure Shell) command.  With the
 <option>--from</option>, the direction is reversed:
 the closure of <replaceable>paths</replaceable> on a remote machine is
 copied to the Nix store on the local machine.</para>
 <para>This command is efficient because it only sends the store paths
 that are missing on the target machine.</para>
 <para>Since <command>nix-copy-closure</command> calls
 <command>ssh</command>, you may be asked to type in the appropriate
 password or passphrase.  In fact, you may be asked
 <emphasis>twice</emphasis> because <command>nix-copy-closure</command>
 currently connects twice to the remote machine, first to get the set
 of paths missing on the target machine, and second to send the dump of
 those paths.  If this bothers you, use
 <command>ssh-agent</command>.</para>
 <refsection><title>Options</title>
 <variablelist>
  <varlistentry><term><option>--to</option></term>
    <listitem><para>Copy the closure of
    <replaceable>paths</replaceable> from the local Nix store to the
    Nix store on <replaceable>machine</replaceable>.  This is the
    default.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--from</option></term>
    <listitem><para>Copy the closure of
    <replaceable>paths</replaceable> from the Nix store on
    <replaceable>machine</replaceable> to the local Nix
    store.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--gzip</option></term>
    <listitem><para>Enable compression of the SSH
    connection.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--include-outputs</option></term>
    <listitem><para>Also copy the outputs of store derivations
    included in the closure.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--use-substitutes</option> / <option>-s</option></term>
    <listitem><para>Attempt to download missing paths on the target
    machine using Nix’s substitute mechanism.  Any paths that cannot
    be substituted on the target are still copied normally from the
    source.  This is useful, for instance, if the connection between
    the source and target machine is slow, but the connection between
    the target machine and <literal>nixos.org</literal> (the default
    binary cache server) is fast.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>-v</option></term>
    <listitem><para>Show verbose output.</para></listitem>
  </varlistentry>
 </variablelist>
 </refsection>
 <refsection><title>Environment variables</title>
 <variablelist>
  <varlistentry><term><envar>NIX_SSHOPTS</envar></term>
    <listitem><para>Additional options to be passed to
    <command>ssh</command> on the command line.</para></listitem>
  </varlistentry>
 </variablelist>
 </refsection>
 <refsection><title>Examples</title>
 <para>Copy Firefox with all its dependencies to a remote machine:
 <screen>
 $ nix-copy-closure --to alice@itchy.labs $(type -tP firefox)</screen>
 </para>
 <para>Copy Subversion from a remote machine and then install it into a
 user environment:
 <screen>
 $ nix-copy-closure --from alice@itchy.labs \
    /nix/store/0dj0503hjxy5mbwlafv1rsbdiyx1gkdy-subversion-1.4.4
 $ nix-env -i /nix/store/0dj0503hjxy5mbwlafv1rsbdiyx1gkdy-subversion-1.4.4
 </screen>
 </para>
 </refsection>
 </refsection>
 </refentry>
--- a/doc/manual/command-ref/nix-daemon.xml
+++ b/doc/manual/command-ref/nix-daemon.xml
@ -1,35 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-daemon</refname>
  <refpurpose>Nix multi-user support daemon</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-daemon</command>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The Nix daemon is necessary in multi-user Nix installations.  It
 performs build actions and other operations on the Nix store on behalf
 of unprivileged users.</para>
 </refsection>
 </refentry>
--- a/doc/manual/command-ref/nix-env.xml
+++ b/doc/manual/command-ref/nix-env.xml
--- a/doc/manual/command-ref/nix-hash.xml
+++ b/doc/manual/command-ref/nix-hash.xml
@ -1,176 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-hash</refname>
  <refpurpose>compute the cryptographic hash of a path</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-hash</command>
    <arg><option>--flat</option></arg>
    <arg><option>--base32</option></arg>
    <arg><option>--truncate</option></arg>
    <arg><option>--type</option> <replaceable>hashAlgo</replaceable></arg>
    <arg choice='plain' rep='repeat'><replaceable>path</replaceable></arg>
  </cmdsynopsis>
  <cmdsynopsis>
    <command>nix-hash</command>
    <arg choice='plain'><option>--to-base16</option></arg>
    <arg choice='plain' rep='repeat'><replaceable>hash</replaceable></arg>
  </cmdsynopsis>
  <cmdsynopsis>
    <command>nix-hash</command>
    <arg choice='plain'><option>--to-base32</option></arg>
    <arg choice='plain' rep='repeat'><replaceable>hash</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The command <command>nix-hash</command> computes the
 cryptographic hash of the contents of each
 <replaceable>path</replaceable> and prints it on standard output.  By
 default, it computes an MD5 hash, but other hash algorithms are
 available as well.  The hash is printed in hexadecimal.  To generate
 the same hash as <command>nix-prefetch-url</command> you have to
 specify multiple arguments, see below for an example.</para>
 <para>The hash is computed over a <emphasis>serialisation</emphasis>
 of each path: a dump of the file system tree rooted at the path.  This
 allows directories and symlinks to be hashed as well as regular files.
 The dump is in the <emphasis>NAR format</emphasis> produced by <link
 linkend="refsec-nix-store-dump"><command>nix-store</command>
 <option>--dump</option></link>.  Thus, <literal>nix-hash
 <replaceable>path</replaceable></literal> yields the same
 cryptographic hash as <literal>nix-store --dump
 <replaceable>path</replaceable> | md5sum</literal>.</para>
 </refsection>
 <refsection><title>Options</title>
 <variablelist>
  <varlistentry><term><option>--flat</option></term>
    <listitem><para>Print the cryptographic hash of the contents of
    each regular file <replaceable>path</replaceable>.  That is, do
    not compute the hash over the dump of
    <replaceable>path</replaceable>.  The result is identical to that
    produced by the GNU commands <command>md5sum</command> and
    <command>sha1sum</command>.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--base32</option></term>
    <listitem><para>Print the hash in a base-32 representation rather
    than hexadecimal.  This base-32 representation is more compact and
    can be used in Nix expressions (such as in calls to
    <function>fetchurl</function>).</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--truncate</option></term>
    <listitem><para>Truncate hashes longer than 160 bits (such as
    SHA-256) to 160 bits.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--type</option> <replaceable>hashAlgo</replaceable></term>
    <listitem><para>Use the specified cryptographic hash algorithm,
    which can be one of <literal>md5</literal>,
    <literal>sha1</literal>, and
    <literal>sha256</literal>.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--to-base16</option></term>
    <listitem><para>Don’t hash anything, but convert the base-32 hash
    representation <replaceable>hash</replaceable> to
    hexadecimal.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--to-base32</option></term>
    <listitem><para>Don’t hash anything, but convert the hexadecimal
    hash representation <replaceable>hash</replaceable> to
    base-32.</para></listitem>
  </varlistentry>
 </variablelist>
 </refsection>
 <refsection><title>Examples</title>
 <para>Computing the same hash as <command>nix-prefetch-url</command>:
 <screen>
 $ nix-prefetch-url file://&lt;(echo test)
 1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
 $ nix-hash --type sha256 --flat --base32 &lt;(echo test)
 1lkgqb6fclns49861dwk9rzb6xnfkxbpws74mxnx01z9qyv1pjpj
 </screen>
 </para>
 <para>Computing hashes:
 <screen>
 $ mkdir test
 $ echo "hello" > test/world
 $ nix-hash test/ <lineannotation>(MD5 hash; default)</lineannotation>
 8179d3caeff1869b5ba1744e5a245c04
 $ nix-store --dump test/ | md5sum <lineannotation>(for comparison)</lineannotation>
 8179d3caeff1869b5ba1744e5a245c04  -
 $ nix-hash --type sha1 test/
 e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
 $ nix-hash --type sha1 --base32 test/
 nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
 $ nix-hash --type sha256 --flat test/
 error: reading file `test/': Is a directory
 $ nix-hash --type sha256 --flat test/world
 5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03</screen>
 </para>
 <para>Converting between hexadecimal and base-32:
 <screen>
 $ nix-hash --type sha1 --to-base32 e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6
 nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
 $ nix-hash --type sha1 --to-base16 nvd61k9nalji1zl9rrdfmsmvyyjqpzg4
 e4fd8ba5f7bbeaea5ace89fe10255536cd60dab6</screen>
 </para>
 </refsection>
 </refentry>
--- a/doc/manual/command-ref/nix-instantiate.xml
+++ b/doc/manual/command-ref/nix-instantiate.xml
@ -1,266 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-instantiate</refname>
  <refpurpose>instantiate store derivations from Nix expressions</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-instantiate</command>
    <group>
      <arg choice='plain'><option>--parse</option></arg>
      <arg choice='plain'>
        <option>--eval</option>
        <arg><option>--strict</option></arg>
        <arg><option>--json</option></arg>
        <arg><option>--xml</option></arg>
      </arg>
    </group>
    <arg><option>--read-write-mode</option></arg>
    <arg><option>--arg</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>--add-root</option> <replaceable>path</replaceable></arg>
    <arg><option>--indirect</option></arg>
    <group>
      <arg choice='plain'><option>--expr</option></arg>
      <arg choice='plain'><option>-E</option></arg>
    </group>
    <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
  </cmdsynopsis>
  <cmdsynopsis>
    <command>nix-instantiate</command>
    <arg choice='plain'><option>--find-file</option></arg>
    <arg choice='plain' rep='repeat'><replaceable>files</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The command <command>nix-instantiate</command> generates <link
 linkend="gloss-derivation">store derivations</link> from (high-level)
 Nix expressions.  It evaluates the Nix expressions in each of
 <replaceable>files</replaceable> (which defaults to
 <replaceable>./default.nix</replaceable>).  Each top-level expression
 should evaluate to a derivation, a list of derivations, or a set of
 derivations.  The paths of the resulting store derivations are printed
 on standard output.</para>
 <para>If <replaceable>files</replaceable> is the character
 <literal>-</literal>, then a Nix expression will be read from standard
 input.</para>
 <para condition="manual">See also <xref linkend="sec-common-options"
 /> for a list of common options.</para>
 </refsection>
 <refsection><title>Options</title>
 <variablelist>
  <varlistentry>
    <term><option>--add-root</option> <replaceable>path</replaceable></term>
    <term><option>--indirect</option></term>
    <listitem><para>See the <link linkend="opt-add-root">corresponding
    options</link> in <command>nix-store</command>.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--parse</option></term>
    <listitem><para>Just parse the input files, and print their
    abstract syntax trees on standard output in ATerm
    format.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--eval</option></term>
    <listitem><para>Just parse and evaluate the input files, and print
    the resulting values on standard output.  No instantiation of
    store derivations takes place.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--find-file</option></term>
    <listitem><para>Look up the given files in Nix’s search path (as
    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
    <literal>/home/alice/nixpkgs/default.nix</literal>.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--strict</option></term>
    <listitem><para>When used with <option>--eval</option>,
    recursively evaluate list elements and attributes.  Normally, such
    sub-expressions are left unevaluated (since the Nix expression
    language is lazy).</para>
    <warning><para>This option can cause non-termination, because lazy
    data structures can be infinitely large.</para></warning>
    </listitem>
  </varlistentry>
  <varlistentry><term><option>--json</option></term>
    <listitem><para>When used with <option>--eval</option>, print the resulting
    value as an JSON representation of the abstract syntax tree rather
    than as an ATerm.</para></listitem>
  </varlistentry>
  <varlistentry><term><option>--xml</option></term>
    <listitem><para>When used with <option>--eval</option>, print the resulting
    value as an XML representation of the abstract syntax tree rather than as
    an ATerm. The schema is the same as that used by the <link
    linkend="builtin-toXML"><function>toXML</function> built-in</link>.
    </para></listitem>
  </varlistentry>
  <varlistentry><term><option>--read-write-mode</option></term>
    <listitem><para>When used with <option>--eval</option>, perform
    evaluation in read/write mode so nix language features that
    require it will still work (at the cost of needing to do
    instantiation of every evaluated derivation). If this option is
    not enabled, there may be uninstantiated store paths in the final
    output.</para>
    </listitem>
  </varlistentry>
 </variablelist>
 <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>Instantiating store derivations from a Nix expression, and
 building them using <command>nix-store</command>:
 <screen>
 $ nix-instantiate test.nix <lineannotation>(instantiate)</lineannotation>
 /nix/store/cigxbmvy6dzix98dxxh9b6shg7ar5bvs-perl-BerkeleyDB-0.26.drv
 $ nix-store -r $(nix-instantiate test.nix) <lineannotation>(build)</lineannotation>
 <replaceable>...</replaceable>
 /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26 <lineannotation>(output path)</lineannotation>
 $ ls -l /nix/store/qhqk4n8ci095g3sdp93x7rgwyh9rdvgk-perl-BerkeleyDB-0.26
 dr-xr-xr-x    2 eelco    users        4096 1970-01-01 01:00 lib
 ...</screen>
 </para>
 <para>You can also give a Nix expression on the command line:
 <screen>
 $ nix-instantiate -E 'with import &lt;nixpkgs> { }; hello'
 /nix/store/j8s4zyv75a724q38cb0r87rlczaiag4y-hello-2.8.drv
 </screen>
 This is equivalent to:
 <screen>
 $ nix-instantiate '&lt;nixpkgs>' -A hello
 </screen>
 </para>
 <para>Parsing and evaluating Nix expressions:
 <screen>
 $ nix-instantiate --parse -E '1 + 2'
 1 + 2
 $ nix-instantiate --eval -E '1 + 2'
 3
 $ nix-instantiate --eval --xml -E '1 + 2'
 <![CDATA[<?xml version='1.0' encoding='utf-8'?>
 <expr>
  <int value="3" />
 </expr>]]></screen>
 </para>
 <para>The difference between non-strict and strict evaluation:
 <screen>
 $ nix-instantiate --eval --xml -E 'rec { x = "foo"; y = x; }'
 <replaceable>...</replaceable><![CDATA[
  <attr name="x">
    <string value="foo" />
  </attr>
  <attr name="y">
    <unevaluated />
  </attr>]]>
 <replaceable>...</replaceable></screen>
 Note that <varname>y</varname> is left unevaluated (the XML
 representation doesn’t attempt to show non-normal forms).
 <screen>
 $ nix-instantiate --eval --xml --strict -E 'rec { x = "foo"; y = x; }'
 <replaceable>...</replaceable><![CDATA[
  <attr name="x">
    <string value="foo" />
  </attr>
  <attr name="y">
    <string value="foo" />
  </attr>]]>
 <replaceable>...</replaceable></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>
--- a/doc/manual/command-ref/nix-prefetch-url.xml
+++ b/doc/manual/command-ref/nix-prefetch-url.xml
@ -1,131 +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"
      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>
 </refmeta>
 <refnamediv>
  <refname>nix-prefetch-url</refname>
  <refpurpose>copy a file from a URL into the store and print its hash</refpurpose>
 </refnamediv>
 <refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-prefetch-url</command>
    <arg><option>--version</option></arg>
    <arg><option>--type</option> <replaceable>hashAlgo</replaceable></arg>
    <arg><option>--print-path</option></arg>
    <arg><option>--unpack</option></arg>
    <arg><option>--name</option> <replaceable>name</replaceable></arg>
    <arg choice='plain'><replaceable>url</replaceable></arg>
    <arg><replaceable>hash</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>
 <refsection><title>Description</title>
 <para>The command <command>nix-prefetch-url</command> downloads the
 file referenced by the URL <replaceable>url</replaceable>, prints its
 cryptographic hash, and copies it into the Nix store.  The file name
 in the store is
 <filename><replaceable>hash</replaceable>-<replaceable>baseName</replaceable></filename>,
 where <replaceable>baseName</replaceable> is everything following the
 final slash in <replaceable>url</replaceable>.</para>
 <para>This command is just a convenience for Nix expression writers.
 Often a Nix expression fetches some source distribution from the
 network using the <literal>fetchurl</literal> expression contained in
 Nixpkgs.  However, <literal>fetchurl</literal> requires a
 cryptographic hash.  If you don't know the hash, you would have to
 download the file first, and then <literal>fetchurl</literal> would
 download it again when you build your Nix expression.  Since
 <literal>fetchurl</literal> uses the same name for the downloaded file
 as <command>nix-prefetch-url</command>, the redundant download can be
 avoided.</para>
 <para>If <replaceable>hash</replaceable> is specified, then a download
 is not performed if the Nix store already contains a file with the
 same hash and base name.  Otherwise, the file is downloaded, and an
 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 option <option>--print-path</option> is used, the path of the
 downloaded file in the Nix store is also printed.</para>
 </refsection>
 <refsection><title>Options</title>
 <variablelist>
  <varlistentry><term><option>--type</option> <replaceable>hashAlgo</replaceable></term>
    <listitem><para>Use the specified cryptographic hash algorithm,
    which can be one of <literal>md5</literal>,
    <literal>sha1</literal>, and
    <literal>sha256</literal>.</para></listitem>
  </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> <replaceable>name</replaceable></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>
 <refsection><title>Examples</title>
 <screen>
 $ nix-prefetch-url ftp://ftp.gnu.org/pub/gnu/hello/hello-2.10.tar.gz
 0ssi1wpaf7plaswqqjwigppsg5fyh99vdlb9kzl7c9lng89ndq1i
 $ 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>
--- a/doc/manual/command-ref/nix-shell.xml
+++ b/doc/manual/command-ref/nix-shell.xml
@ -1,397 +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"
      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>
    <arg><option>--keep</option> <replaceable>name</replaceable></arg>
    <group choice='req'>
      <arg choice='plain'>
        <group choice='req'>
          <arg choice='plain'><option>--packages</option></arg>
          <arg choice='plain'><option>-p</option></arg>
        </group>
        <arg choice='plain' rep='repeat'><replaceable>packages</replaceable></arg>
      </arg>
      <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> <replaceable>packages</replaceable>…</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>
  <varlistentry><term><option>--keep</option> <replaceable>name</replaceable></term>
    <listitem><para>When a <option>--pure</option> shell is started,
    keep the listed environment variables.</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>Sometimes you need to pass a simple Nix expression to customize
 a package like Terraform:
 <programlisting><![CDATA[
 #! /usr/bin/env nix-shell
 #! nix-shell -i bash -p "terraform.withPlugins (plugins: [ plugins.openstack ])"
 terraform apply
 ]]></programlisting>
 <note><para>You must use double quotes (<literal>"</literal>) when
 passing a simple Nix expression in a nix-shell shebang.</para></note>
 </para>
 <para>Finally, using the merging of multiple nix-shell shebangs the
 following Haskell script uses a specific branch of Nixpkgs/NixOS (the
 18.03 stable branch):
 <programlisting><![CDATA[
 #! /usr/bin/env nix-shell
 #! nix-shell -i runghc -p "haskellPackages.ghcWithPackages (ps: [ps.HTTP ps.tagsoup])"
 #! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixos-18.03.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>
--- a/doc/manual/command-ref/nix-store.xml
+++ b/doc/manual/command-ref/nix-store.xml
--- a/doc/manual/command-ref/opt-common-syn.xml
+++ b/doc/manual/command-ref/opt-common-syn.xml
@ -1,64 +0,0 @@
 <nop xmlns="http://docbook.org/ns/docbook">
 <arg><option>--help</option></arg>
 <arg><option>--version</option></arg>
 <arg rep='repeat'>
  <group choice='req'>
    <arg choice='plain'><option>--verbose</option></arg>
    <arg choice='plain'><option>-v</option></arg>
  </group>
 </arg>
 <arg>
  <arg choice='plain'><option>--quiet</option></arg>
 </arg>
 <arg>
  <group choice='plain'>
    <arg choice='plain'><option>--no-build-output</option></arg>
    <arg choice='plain'><option>-Q</option></arg>
  </group>
 </arg>
 <arg>
  <group choice='req'>
    <arg choice='plain'><option>--max-jobs</option></arg>
    <arg choice='plain'><option>-j</option></arg>
  </group>
  <replaceable>number</replaceable>
 </arg>
 <arg>
  <option>--cores</option>
  <replaceable>number</replaceable>
 </arg>
 <arg>
  <option>--max-silent-time</option>
  <replaceable>number</replaceable>
 </arg>
 <arg>
  <option>--timeout</option>
  <replaceable>number</replaceable>
 </arg>
 <arg>
  <group choice='plain'>
    <arg choice='plain'><option>--keep-going</option></arg>
    <arg choice='plain'><option>-k</option></arg>
  </group>
 </arg>
 <arg>
  <group choice='plain'>
    <arg choice='plain'><option>--keep-failed</option></arg>
    <arg choice='plain'><option>-K</option></arg>
  </group>
 </arg>
 <arg><option>--fallback</option></arg>
 <arg><option>--readonly-mode</option></arg>
 <arg>
  <option>-I</option>
  <replaceable>path</replaceable>
 </arg>
 <arg>
  <option>--option</option>
  <replaceable>name</replaceable>
  <replaceable>value</replaceable>
 </arg>
 <sbr />
 </nop>
--- a/doc/manual/command-ref/opt-common.xml
+++ b/doc/manual/command-ref/opt-common.xml
@ -1,358 +0,0 @@
 <chapter xmlns="http://docbook.org/ns/docbook" xml:id="sec-common-options">
 <title>Common Options</title>
 <para>Most Nix commands accept the following command-line options:</para>
 <variablelist xml:id="opt-common">
 <varlistentry><term><option>--help</option></term>
  <listitem><para>Prints out a summary of the command syntax and
  exits.</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--version</option></term>
  <listitem><para>Prints out the Nix version number on standard output
  and exits.</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--verbose</option> / <option>-v</option></term>
  <listitem>
  <para>Increases the level of verbosity of diagnostic messages
  printed on standard error.  For each Nix operation, the information
  printed on standard output is well-defined; any diagnostic
  information is printed on standard error, never on standard
  output.</para>
  <para>This option may be specified repeatedly.  Currently, the
  following verbosity levels exist:</para>
  <variablelist>
    <varlistentry><term>0</term>
    <listitem><para>“Errors only”: only print messages
    explaining why the Nix invocation failed.</para></listitem>
    </varlistentry>
    <varlistentry><term>1</term>
    <listitem><para>“Informational”: print
    <emphasis>useful</emphasis> messages about what Nix is doing.
    This is the default.</para></listitem>
    </varlistentry>
    <varlistentry><term>2</term>
    <listitem><para>“Talkative”: print more informational
    messages.</para></listitem>
    </varlistentry>
    <varlistentry><term>3</term>
    <listitem><para>“Chatty”: print even more
    informational messages.</para></listitem>
    </varlistentry>
    <varlistentry><term>4</term>
    <listitem><para>“Debug”: print debug
    information.</para></listitem>
    </varlistentry>
    <varlistentry><term>5</term>
    <listitem><para>“Vomit”: print vast amounts of debug
    information.</para></listitem>
    </varlistentry>
  </variablelist>
  </listitem>
 </varlistentry>
 <varlistentry><term><option>--quiet</option></term>
  <listitem>
  <para>Decreases the level of verbosity of diagnostic messages
  printed on standard error.  This is the inverse option to
  <option>-v</option> / <option>--verbose</option>.
  </para>
  <para>This option may be specified repeatedly.  See the previous
  verbosity levels list.</para>
  </listitem>
 </varlistentry>
 <varlistentry><term><option>--no-build-output</option> / <option>-Q</option></term>
  <listitem><para>By default, output written by builders to standard
  output and standard error is echoed to the Nix command's standard
  error.  This option suppresses this behaviour.  Note that the
  builder's standard output and error are always written to a log file
  in
  <filename><replaceable>prefix</replaceable>/nix/var/log/nix</filename>.</para></listitem>
 </varlistentry>
 <varlistentry xml:id="opt-max-jobs"><term><option>--max-jobs</option> / <option>-j</option>
 <replaceable>number</replaceable></term>
  <listitem><para>Sets the maximum number of build jobs that Nix will
  perform in parallel to the specified number.  Specify
  <literal>auto</literal> to use the number of CPUs in the system.
  The default is specified by the <link
  linkend='conf-max-jobs'><literal>max-jobs</literal></link>
  configuration setting, which itself defaults to
  <literal>1</literal>.  A higher value is useful on SMP systems or to
  exploit I/O latency.</para></listitem>
 </varlistentry>
 <varlistentry xml:id="opt-cores"><term><option>--cores</option></term>
  <listitem><para>Sets the value of the <envar>NIX_BUILD_CORES</envar>
  environment variable in the invocation of builders.  Builders can
  use this variable at their discretion to control the maximum amount
  of parallelism.  For instance, in Nixpkgs, if the derivation
  attribute <varname>enableParallelBuilding</varname> is set to
  <literal>true</literal>, the builder passes the
  <option>-j<replaceable>N</replaceable></option> flag to GNU Make.
  It defaults to the value of the <link
  linkend='conf-cores'><literal>cores</literal></link>
  configuration setting, if set, or <literal>1</literal> otherwise.
  The value <literal>0</literal> means that the builder should use all
  available CPU cores in the system.</para></listitem>
 </varlistentry>
 <varlistentry xml:id="opt-max-silent-time"><term><option>--max-silent-time</option></term>
  <listitem><para>Sets the maximum number of seconds that a builder
  can go without producing any data on standard output or standard
  error.  The default is specified by the <link
  linkend='conf-max-silent-time'><literal>max-silent-time</literal></link>
  configuration setting.  <literal>0</literal> means no
  time-out.</para></listitem>
 </varlistentry>
 <varlistentry xml:id="opt-timeout"><term><option>--timeout</option></term>
  <listitem><para>Sets the maximum number of seconds that a builder
  can run.  The default is specified by the <link
  linkend='conf-timeout'><literal>timeout</literal></link>
  configuration setting.  <literal>0</literal> means no
  timeout.</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--keep-going</option> / <option>-k</option></term>
  <listitem><para>Keep going in case of failed builds, to the
  greatest extent possible.  That is, if building an input of some
  derivation fails, Nix will still build the other inputs, but not the
  derivation itself.  Without this option, Nix stops if any build
  fails (except for builds of substitutes), possibly killing builds in
  progress (in case of parallel or distributed builds).</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--keep-failed</option> / <option>-K</option></term>
  <listitem><para>Specifies that in case of a build failure, the
  temporary directory (usually in <filename>/tmp</filename>) in which
  the build takes place should not be deleted.  The path of the build
  directory is printed as an informational message.
    </para>
  </listitem>
 </varlistentry>
 <varlistentry><term><option>--fallback</option></term>
  <listitem>
  <para>Whenever Nix attempts to build a derivation for which
  substitutes are known for each output path, but realising the output
  paths through the substitutes fails, fall back on building the
  derivation.</para>
  <para>The most common scenario in which this is useful is when we
  have registered substitutes in order to perform binary distribution
  from, say, a network repository.  If the repository is down, the
  realisation of the derivation will fail.  When this option is
  specified, Nix will build the derivation instead.  Thus,
  installation from binaries falls back on installation from source.
  This option is not the default since it is generally not desirable
  for a transient failure in obtaining the substitutes to lead to a
  full build from source (with the related consumption of
  resources).</para>
  </listitem>
 </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>
  <listitem><para>When this option is used, no attempt is made to open
  the Nix database.  Most Nix operations do need database access, so
  those operations will fail.</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--arg</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term>
  <listitem><para>This option is accepted by
  <command>nix-env</command>, <command>nix-instantiate</command> and
  <command>nix-build</command>.  When evaluating Nix expressions, the
  expression evaluator will automatically try to call functions that
  it encounters.  It can automatically call functions for which every
  argument has a <link linkend='ss-functions'>default value</link>
  (e.g., <literal>{ <replaceable>argName</replaceable> ?
  <replaceable>defaultValue</replaceable> }:
  <replaceable>...</replaceable></literal>).  With
  <option>--arg</option>, you can also call functions that have
  arguments without a default value (or override a default value).
  That is, if the evaluator encounters a function with an argument
  named <replaceable>name</replaceable>, it will call it with value
  <replaceable>value</replaceable>.</para>
  <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.
  system ? builtins.currentSystem
  <replaceable>...</replaceable>
 }: <replaceable>...</replaceable></programlisting>
  So if you call this Nix expression (e.g., when you do
  <literal>nix-env -i <replaceable>pkgname</replaceable></literal>),
  the function will be called automatically using the value <link
  linkend='builtin-currentSystem'><literal>builtins.currentSystem</literal></link>
  for the <literal>system</literal> argument.  You can override this
  using <option>--arg</option>, e.g., <literal>nix-env -i
  <replaceable>pkgname</replaceable> --arg system
  \"i686-freebsd\"</literal>.  (Note that since the argument is a Nix
  string literal, you have to escape the quotes.)</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--argstr</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term>
  <listitem><para>This option is like <option>--arg</option>, only the
  value is not a Nix expression but a string.  So instead of
  <literal>--arg system \"i686-linux\"</literal> (the outer quotes are
  to keep the shell happy) you can say <literal>--argstr system
  i686-linux</literal>.</para></listitem>
 </varlistentry>
 <varlistentry xml:id="opt-attr"><term><option>--attr</option> / <option>-A</option>
 <replaceable>attrPath</replaceable></term>
  <listitem><para>Select an attribute from the top-level Nix
  expression being evaluated.  (<command>nix-env</command>,
  <command>nix-instantiate</command>, <command>nix-build</command> and
  <command>nix-shell</command> only.)  The <emphasis>attribute
  path</emphasis> <replaceable>attrPath</replaceable> is a sequence of
  attribute names separated by dots.  For instance, given a top-level
  Nix expression <replaceable>e</replaceable>, the attribute path
  <literal>xorg.xorgserver</literal> would cause the expression
  <literal><replaceable>e</replaceable>.xorg.xorgserver</literal> to
  be used.  See <link
  linkend='refsec-nix-env-install-examples'><command>nix-env
  --install</command></link> for some concrete examples.</para>
  <para>In addition to attribute names, you can also specify array
  indices.  For instance, the attribute path
  <literal>foo.3.bar</literal> selects the <literal>bar</literal>
  attribute of the fourth element of the array in the
  <literal>foo</literal> attribute of the top-level
  expression.</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--expr</option> / <option>-E</option></term>
  <listitem><para>Interpret the command line arguments as a list of
  Nix expressions to be parsed and evaluated, rather than as a list
  of file names of Nix expressions.
  (<command>nix-instantiate</command>, <command>nix-build</command>
  and <command>nix-shell</command> only.)</para></listitem>
 </varlistentry>
 <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
  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>
 <varlistentry><term><option>--option</option> <replaceable>name</replaceable> <replaceable>value</replaceable></term>
  <listitem><para>Set the Nix configuration option
  <replaceable>name</replaceable> to <replaceable>value</replaceable>.
  This overrides settings in the Nix configuration file (see
  <citerefentry><refentrytitle>nix.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).</para></listitem>
 </varlistentry>
 <varlistentry><term><option>--repair</option></term>
  <listitem><para>Fix corrupted or missing store paths by
  redownloading or rebuilding them.  Note that this is slow because it
  requires computing a cryptographic hash of the contents of every
  path in the closure of the build.  Also note the warning under
  <command>nix-store --repair-path</command>.</para></listitem>
 </varlistentry>
 </variablelist>
 </chapter>
--- a/doc/manual/command-ref/opt-inst-syn.xml
+++ b/doc/manual/command-ref/opt-inst-syn.xml
@ -1,22 +0,0 @@
 <nop xmlns="http://docbook.org/ns/docbook">
  <arg>
    <group choice='req'>
      <arg choice='plain'><option>--prebuilt-only</option></arg>
      <arg choice='plain'><option>-b</option></arg>
    </group>
  </arg>
  <arg>
    <group choice='req'>
      <arg choice='plain'><option>--attr</option></arg>
      <arg choice='plain'><option>-A</option></arg>
    </group>
  </arg>
  <arg><option>--from-expression</option></arg>
  <arg><option>-E</option></arg>
  <arg><option>--from-profile</option> <replaceable>path</replaceable></arg>
 </nop>
--- a/doc/manual/command-ref/utilities.xml
+++ b/doc/manual/command-ref/utilities.xml
@ -1,20 +0,0 @@
 <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>
--- a/doc/manual/custom.css
+++ b/doc/manual/custom.css
@ -0,0 +1,7 @@
 h1:not(:first-of-type) {
    margin-top: 1.3em;
 }
 h2 {
    margin-top: 1em;
 }
--- a/doc/manual/expressions/advanced-attributes.xml
+++ b/doc/manual/expressions/advanced-attributes.xml
@ -1,340 +0,0 @@
 <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>disallowedReferences</varname></term>
    <listitem><para>The optional attribute
    <varname>disallowedReferences</varname> specifies a list of illegal
    references (dependencies) of the output of the builder.  For
    example,
 <programlisting>
 disallowedReferences = [ foo ];
 </programlisting>
    enforces that the output of a derivation cannot have a direct runtime
    dependencies on the derivation <varname>foo</varname>.</para></listitem>
  </varlistentry>
  <varlistentry><term><varname>disallowedRequisites</varname></term>
    <listitem><para>This attribute is similar to
    <varname>disallowedReferences</varname>, but it specifies illegal
    requisites for the whole closure, so all the dependencies
    recursively.  For example,
 <programlisting>
 disallowedRequisites = [ foobar ];
 </programlisting>
    enforces that the output of a derivation cannot have any
    runtime dependency on <varname>foobar</varname> or any other derivation
    depending recursively on <varname>foobar</varname>.</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>
    <warning><para><varname>impureEnvVars</varname> implementation takes
    environment variables from the current builder process. When a daemon is
    building its environmental variables are used. Without the daemon, the
    environmental variables come from the environment of the
    <command>nix-build</command>.</para></warning></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;
  sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
 }
 </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;
  sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
 }
 </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, sha256 }:
 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 SHA256 hash <varname>sha256</varname>.
  outputHashMode = "flat";
  outputHashAlgo = "sha256";
  outputHash = sha256;
  inherit url;
 }
 </programlisting>
    </para>
    <para>The <varname>outputHashAlgo</varname> attribute specifies
    the hash algorithm used to compute the hash.  It can currently be
    <literal>"sha1"</literal>, <literal>"sha256"</literal> or
    <literal>"sha512"</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>sha256sum</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> and <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>
  <varlistentry><term><varname>allowSubstitutes</varname></term>
    <listitem><para>If this attribute is set to
    <literal>false</literal>, then Nix will always build this
    derivation; it will not try to substitute its outputs. This is
    useful for very trivial derivations (such as
    <function>writeText</function> in Nixpkgs) that are cheaper to
    build than to substitute from a binary cache.</para></listitem>
  </varlistentry>
 </variablelist>
 </section>
--- a/doc/manual/expressions/arguments-variables.xml
+++ b/doc/manual/expressions/arguments-variables.xml
@ -1,121 +0,0 @@
 <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>
--- a/doc/manual/expressions/build-script.xml
+++ b/doc/manual/expressions/build-script.xml
@ -1,119 +0,0 @@
 <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>
--- a/doc/manual/expressions/builder-syntax.xml
+++ b/doc/manual/expressions/builder-syntax.xml
@ -1,119 +0,0 @@
 <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>
--- a/doc/manual/expressions/builtins.xml
+++ b/doc/manual/expressions/builtins.xml
--- a/doc/manual/expressions/derivations.xml
+++ b/doc/manual/expressions/derivations.xml
@ -1,211 +0,0 @@
 <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>outputs</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>
--- a/doc/manual/expressions/expression-language.xml
+++ b/doc/manual/expressions/expression-language.xml
@ -1,30 +0,0 @@
 <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>
--- a/doc/manual/expressions/expression-syntax.xml
+++ b/doc/manual/expressions/expression-syntax.xml
@ -1,148 +0,0 @@
 <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;
    sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
  };
  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 a SHA-256 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>
--- a/doc/manual/expressions/generic-builder.xml
+++ b/doc/manual/expressions/generic-builder.xml
@ -1,98 +0,0 @@
 <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>
--- a/doc/manual/expressions/language-constructs.xml
+++ b/doc/manual/expressions/language-constructs.xml
@ -1,391 +0,0 @@
 <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 xml:id="sect-let-expressions"><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 or in a let-expression 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>
 is equivalent to
 <programlisting>
 let x = 123; in
 { x = x;
  y = 456;
 }</programlisting>
 and both evaluate 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>
 <para>
 Summarizing the fragment
 <programlisting>
 ...
 inherit x y z;
 inherit (src-set) a b c;
 ...</programlisting>
 is equivalent to
 <programlisting>
 ...
 x = x; y = y; z = z;
 a = src-set.a; b = src-set.b; c = src-set.c;
 ...</programlisting>
 when used while defining local variables in a let-expression or
 while defining a 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>let</literal>-expression.</para>
 <para>The bindings introduced by <literal>with</literal> do not shadow bindings
 introduced by other means, e.g.
 <programlisting>
 let a = 3; in with { a = 1; }; let a = 4; in with { a = 2; }; ...</programlisting>
 establishes the same scope as
 <programlisting>
 let a = 1; in let a = 2; in let a = 3; in let a = 4; in ...</programlisting>
 </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>
--- a/doc/manual/expressions/language-operators.xml
+++ b/doc/manual/expressions/language-operators.xml
@ -1,135 +0,0 @@
 <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><literal>-</literal> <replaceable>e</replaceable></entry>
        <entry>none</entry>
        <entry>Arithmetic negation.</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>,
          <replaceable>e1</replaceable> <literal>/</literal> <replaceable>e2</replaceable>
        </entry>
        <entry>left</entry>
        <entry>Arithmetic multiplication and division.</entry>
      </row>
      <row>
        <entry>
          <replaceable>e1</replaceable> <literal>+</literal> <replaceable>e2</replaceable>,
          <replaceable>e1</replaceable> <literal>-</literal> <replaceable>e2</replaceable>
        </entry>
        <entry>left</entry>
        <entry>Arithmetic addition and subtraction.  String or path concatenation (only by <literal>+</literal>).</entry>
      </row>
      <row>
        <entry><literal>!</literal> <replaceable>e</replaceable></entry>
        <entry>none</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>&lt;</literal> <replaceable>e2</replaceable>,
          <replaceable>e1</replaceable> <literal>&gt;</literal> <replaceable>e2</replaceable>,
          <replaceable>e1</replaceable> <literal>&lt;=</literal> <replaceable>e2</replaceable>,
          <replaceable>e1</replaceable> <literal>&gt;=</literal> <replaceable>e2</replaceable>
        </entry>
        <entry>none</entry>
        <entry>Arithmetic comparison.</entry>
      </row>
      <row>
        <entry>
          <replaceable>e1</replaceable> <literal>==</literal> <replaceable>e2</replaceable>,
          <replaceable>e1</replaceable> <literal>!=</literal> <replaceable>e2</replaceable>
        </entry>
        <entry>none</entry>
        <entry>Equality and 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>
--- a/doc/manual/expressions/language-values.xml
+++ b/doc/manual/expressions/language-values.xml
@ -1,313 +0,0 @@
 <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>. <literal>$</literal> removes any special meaning
    from the following <literal>$</literal>. Linefeed, carriage-return and tab
    characters can be written as <literal>''\n</literal>,
    <literal>''\r</literal>, <literal>''\t</literal>, and <literal>''\</literal>
    escapes any other character.
    </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>
--- a/doc/manual/expressions/simple-building-testing.xml
+++ b/doc/manual/expressions/simple-building-testing.xml
@ -1,84 +0,0 @@
 <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>
 </section>
--- a/doc/manual/expressions/simple-expression.xml
+++ b/doc/manual/expressions/simple-expression.xml
@ -1,47 +0,0 @@
 <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>
--- a/doc/manual/expressions/writing-nix-expressions.xml
+++ b/doc/manual/expressions/writing-nix-expressions.xml
@ -1,26 +0,0 @@
 <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>
--- a/doc/manual/generate-builtins.nix
+++ b/doc/manual/generate-builtins.nix
@ -0,0 +1,14 @@
 with builtins;
 with import ./utils.nix;
 builtins:
 concatStrings (map
  (name:
    let builtin = builtins.${name}; in
    "  - `builtins.${name}` " + concatStringsSep " " (map (s: "*${s}*") builtin.args)
    + "  \n\n"
    + concatStrings (map (s: "    ${s}\n") (splitLines builtin.doc)) + "\n\n"
  )
  (attrNames builtins))
--- a/doc/manual/generate-manpage.nix
+++ b/doc/manual/generate-manpage.nix
@ -0,0 +1,92 @@
 command:
 with builtins;
 with import ./utils.nix;
 let
  showCommand =
    { command, def, filename }:
    "# Name\n\n"
    + "`${command}` - ${def.description}\n\n"
    + "# Synopsis\n\n"
    + showSynopsis { inherit command; args = def.args; }
    + (if def.commands or {} != {}
       then
         let
           categories = sort (x: y: x.id < y.id) (unique (map (cmd: cmd.category) (attrValues def.commands)));
           listCommands = cmds:
             concatStrings (map (name:
               "* [`${command} ${name}`](./${appendName filename name}.md) - ${cmds.${name}.description}\n")
               (attrNames cmds));
         in
         "where *subcommand* is one of the following:\n\n"
         # FIXME: group by category
         + (if length categories > 1
            then
              concatStrings (map
                (cat:
                  "**${toString cat.description}:**\n\n"
                  + listCommands (filterAttrs (n: v: v.category == cat) def.commands)
                  + "\n"
                ) categories)
              + "\n"
            else
              listCommands def.commands
              + "\n")
       else "")
    + (if def ? doc
       then def.doc + "\n\n"
       else "")
    + (let s = showOptions def.flags; in
       if s != ""
       then "# Options\n\n${s}"
       else "")
  ;
  appendName = filename: name: (if filename == "nix" then "nix3" else filename) + "-" + name;
  showOptions = flags:
    let
      categories = sort builtins.lessThan (unique (map (cmd: cmd.category) (attrValues flags)));
    in
      concatStrings (map
        (cat:
          (if cat != ""
           then "**${cat}:**\n\n"
           else "")
          + concatStrings
            (map (longName:
              let
                flag = flags.${longName};
              in
                "  - `--${longName}`"
                + (if flag ? shortName then " / `-${flag.shortName}`" else "")
                + (if flag ? labels then " " + (concatStringsSep " " (map (s: "*${s}*") flag.labels)) else "")
                + "  \n"
                + "    " + flag.description + "\n\n"
            ) (attrNames (filterAttrs (n: v: v.category == cat) flags))))
        categories);
  showSynopsis =
    { command, args }:
    "`${command}` [*option*...] ${concatStringsSep " "
      (map (arg: "*${arg.label}*" + (if arg ? arity then "" else "...")) args)}\n\n";
  processCommand = { command, def, filename }:
    [ { name = filename + ".md"; value = showCommand { inherit command def filename; }; inherit command; } ]
    ++ concatMap
      (name: processCommand {
        filename = appendName filename name;
        command = command + " " + name;
        def = def.commands.${name};
      })
      (attrNames def.commands or {});
 in
 let
  manpages = processCommand { filename = "nix"; command = "nix"; def = command; };
  summary = concatStrings (map (manpage: "    - [${manpage.command}](command-ref/new-cli/${manpage.name})\n") manpages);
 in
 (listToAttrs manpages) // { "SUMMARY.md" = summary; }
--- a/doc/manual/generate-options.nix
+++ b/doc/manual/generate-options.nix
@ -0,0 +1,26 @@
 with builtins;
 with import ./utils.nix;
 options:
 concatStrings (map
  (name:
    let option = options.${name}; in
    "  - `${name}`  \n\n"
    + concatStrings (map (s: "    ${s}\n") (splitLines option.description)) + "\n\n"
    + "    **Default:** " + (
      if option.value == "" || option.value == []
      then "*empty*"
      else if isBool option.value
      then (if option.value then "`true`" else "`false`")
      else
        # n.b. a StringMap value type is specified as a string, but
        # this shows the value type.  The empty stringmap is "null" in
        # JSON, but that converts to "{ }" here.
        (if isAttrs option.value then "`\"\"`"
         else "`" + toString option.value + "`")) + "\n\n"
    + (if option.aliases != []
       then "    **Deprecated alias:** " + (concatStringsSep ", " (map (s: "`${s}`") option.aliases)) + "\n\n"
       else "")
    )
  (attrNames options))
--- a/doc/manual/glossary/glossary.xml
+++ b/doc/manual/glossary/glossary.xml
@ -1,199 +0,0 @@
 <appendix xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xml:id="part-glossary">
 <title>Glossary</title>
 <glosslist>
 <glossentry xml:id="gloss-derivation"><glossterm>derivation</glossterm>
  <glossdef><para>A description of a build action.  The result of a
  derivation is a store object.  Derivations are typically specified
  in Nix expressions using the <link
  linkend="ssec-derivation"><function>derivation</function>
  primitive</link>.  These are translated into low-level
  <emphasis>store derivations</emphasis> (implicitly by
  <command>nix-env</command> and <command>nix-build</command>, or
  explicitly by <command>nix-instantiate</command>).</para></glossdef>
 </glossentry>
 <glossentry><glossterm>store</glossterm>
  <glossdef><para>The location in the file system where store objects
  live.  Typically <filename>/nix/store</filename>.</para></glossdef>
 </glossentry>
 <glossentry><glossterm>store path</glossterm>
  <glossdef><para>The location in the file system of a store object,
  i.e., an immediate child of the Nix store
  directory.</para></glossdef>
 </glossentry>
 <glossentry><glossterm>store object</glossterm>
  <glossdef><para>A file that is an immediate child of the Nix store
  directory.  These can be regular files, but also entire directory
  trees.  Store objects can be sources (objects copied from outside of
  the store), derivation outputs (objects produced by running a build
  action), or derivations (files describing a build
  action).</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-substitute"><glossterm>substitute</glossterm>
  <glossdef><para>A substitute is a command invocation stored in the
  Nix database that describes how to build a store object, bypassing
  the normal build mechanism (i.e., derivations).  Typically, the
  substitute builds the store object by downloading a pre-built
  version of the store object from some server.</para></glossdef>
 </glossentry>
 <glossentry><glossterm>purity</glossterm>
  <glossdef><para>The assumption that equal Nix derivations when run
  always produce the same output.  This cannot be guaranteed in
  general (e.g., a builder can rely on external inputs such as the
  network or the system time) but the Nix model assumes
  it.</para></glossdef>
 </glossentry>
 <glossentry><glossterm>Nix expression</glossterm>
  <glossdef><para>A high-level description of software packages and
  compositions thereof.  Deploying software using Nix entails writing
  Nix expressions for your packages.  Nix expressions are translated
  to derivations that are stored in the Nix store.  These derivations
  can then be built.</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-reference"><glossterm>reference</glossterm>
  <glossdef>
    <para>A store path <varname>P</varname> is said to have a
    reference to a store path <varname>Q</varname> if the store object
    at <varname>P</varname> contains the path <varname>Q</varname>
    somewhere. The <emphasis>references</emphasis> of a store path are
    the set of store paths to which it has a reference.
    </para>
    <para>A derivation can reference other derivations and sources
    (but not output paths), whereas an output path only references other
    output paths.
    </para>
  </glossdef>
 </glossentry>
 <glossentry xml:id="gloss-reachable"><glossterm>reachable</glossterm>
  <glossdef><para>A store path <varname>Q</varname> is reachable from
  another store path <varname>P</varname> if <varname>Q</varname> is in the
  <link linkend="gloss-closure">closure</link> of the
  <link linkend="gloss-reference">references</link> relation.
  </para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-closure"><glossterm>closure</glossterm>
  <glossdef><para>The closure of a store path is the set of store
  paths that are directly or indirectly “reachable” from that store
  path; that is, it’s the closure of the path under the <link
  linkend="gloss-reference">references</link> relation. For a package, the
  closure of its derivation is equivalent to the build-time
  dependencies, while the closure of its output path is equivalent to its
  runtime dependencies. For correct deployment it is necessary to deploy whole
  closures, since otherwise at runtime files could be missing. The command
  <command>nix-store -qR</command> prints out closures of store paths.
  </para>
  <para>As an example, if the store object at path <varname>P</varname> contains
  a reference to path <varname>Q</varname>, then <varname>Q</varname> is
  in the closure of <varname>P</varname>. Further, if <varname>Q</varname>
  references <varname>R</varname> then <varname>R</varname> is also in
  the closure of <varname>P</varname>.
  </para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-output-path"><glossterm>output path</glossterm>
  <glossdef><para>A store path produced by a derivation.</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-deriver"><glossterm>deriver</glossterm>
  <glossdef><para>The deriver of an <link
  linkend="gloss-output-path">output path</link> is the store
  derivation that built it.</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-validity"><glossterm>validity</glossterm>
  <glossdef><para>A store path is considered
  <emphasis>valid</emphasis> if it exists in the file system, is
  listed in the Nix database as being valid, and if all paths in its
  closure are also valid.</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-user-env"><glossterm>user environment</glossterm>
  <glossdef><para>An automatically generated store object that
  consists of a set of symlinks to “active” applications, i.e., other
  store paths.  These are generated automatically by <link
  linkend="sec-nix-env"><command>nix-env</command></link>.  See <xref
  linkend="sec-profiles" />.</para>
  </glossdef>
 </glossentry>
 <glossentry xml:id="gloss-profile"><glossterm>profile</glossterm>
  <glossdef><para>A symlink to the current <link
  linkend="gloss-user-env">user environment</link> of a user, e.g.,
  <filename>/nix/var/nix/profiles/default</filename>.</para></glossdef>
 </glossentry>
 <glossentry xml:id="gloss-nar"><glossterm>NAR</glossterm>
  <glossdef><para>A <emphasis>N</emphasis>ix
  <emphasis>AR</emphasis>chive.  This is a serialisation of a path in
  the Nix store.  It can contain regular files, directories and
  symbolic links.  NARs are generated and unpacked using
  <command>nix-store --dump</command> and <command>nix-store
  --restore</command>.</para></glossdef>
 </glossentry>
 </glosslist>
 </appendix>
--- a/doc/manual/hacking.xml
+++ b/doc/manual/hacking.xml
@ -1,41 +0,0 @@
 <appendix xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink"
          xml:id="chap-hacking">
 <title>Hacking</title>
 <para>This section provides some notes on how to hack on Nix.  To get
 the latest version of Nix from GitHub:
 <screen>
 $ git clone git://github.com/NixOS/nix.git
 $ cd nix
 </screen>
 </para>
 <para>To build it and its dependencies:
 <screen>
 $ nix-build release.nix -A build.x86_64-linux
 </screen>
 </para>
 <para>To build all dependencies and start a shell in which all
 environment variables are set up so that those dependencies can be
 found:
 <screen>
 $ nix-shell
 </screen>
 To build Nix itself in this shell:
 <screen>
 [nix-shell]$ ./bootstrap.sh
 [nix-shell]$ configurePhase
 [nix-shell]$ make
 </screen>
 To install it in <literal>$(pwd)/inst</literal> and test it:
 <screen>
 [nix-shell]$ make install
 [nix-shell]$ make installcheck
 </screen>
 </para>
 </appendix>
--- a/doc/manual/highlight.pack.js
+++ b/doc/manual/highlight.pack.js
--- a/doc/manual/images/callouts/1.gif
+++ b/doc/manual/images/callouts/1.gif
--- a/doc/manual/images/callouts/10.gif
+++ b/doc/manual/images/callouts/10.gif
--- a/doc/manual/images/callouts/11.gif
+++ b/doc/manual/images/callouts/11.gif
--- a/doc/manual/images/callouts/12.gif
+++ b/doc/manual/images/callouts/12.gif
--- a/doc/manual/images/callouts/13.gif
+++ b/doc/manual/images/callouts/13.gif
--- a/doc/manual/images/callouts/14.gif
+++ b/doc/manual/images/callouts/14.gif
--- a/doc/manual/images/callouts/15.gif
+++ b/doc/manual/images/callouts/15.gif
--- a/doc/manual/images/callouts/2.gif
+++ b/doc/manual/images/callouts/2.gif
--- a/doc/manual/images/callouts/3.gif
+++ b/doc/manual/images/callouts/3.gif
--- a/doc/manual/images/callouts/4.gif
+++ b/doc/manual/images/callouts/4.gif
--- a/doc/manual/images/callouts/5.gif
+++ b/doc/manual/images/callouts/5.gif
--- a/doc/manual/images/callouts/6.gif
+++ b/doc/manual/images/callouts/6.gif
--- a/doc/manual/images/callouts/7.gif
+++ b/doc/manual/images/callouts/7.gif
--- a/doc/manual/images/callouts/8.gif
+++ b/doc/manual/images/callouts/8.gif
--- a/doc/manual/images/callouts/9.gif
+++ b/doc/manual/images/callouts/9.gif
--- a/doc/manual/installation/building-source.xml
+++ b/doc/manual/installation/building-source.xml
@ -1,49 +0,0 @@
 <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>
--- a/doc/manual/installation/env-variables.xml
+++ b/doc/manual/installation/env-variables.xml
@ -1,71 +0,0 @@
 <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>
 <section xml:id="sec-nix-ssl-cert-file">
 <title><envar>NIX_SSL_CERT_FILE</envar></title>
 <para>If you need to specify a custom certificate bundle to account
 for an HTTPS-intercepting man in the middle proxy, you must specify
 the path to the certificate bundle in the environment variable
 <envar>NIX_SSL_CERT_FILE</envar>.</para>
 <para>If you don't specify a <envar>NIX_SSL_CERT_FILE</envar>
 manually, Nix will install and use its own certificate
 bundle.</para>
 <procedure>
  <step><para>Set the environment variable and install Nix</para>
    <screen>
 $ export NIX_SSL_CERT_FILE=/etc/ssl/my-certificate-bundle.crt
 $ sh &lt;(curl https://nixos.org/nix/install)
 </screen></step>
  <step><para>In the shell profile and rc files (for example,
  <filename>/etc/bashrc</filename>, <filename>/etc/zshrc</filename>),
  add the following line:</para>
 <programlisting>
 export NIX_SSL_CERT_FILE=/etc/ssl/my-certificate-bundle.crt
 </programlisting>
 </step>
 </procedure>
 <note><para>You must not add the export and then do the install, as
 the Nix installer will detect the presense of Nix configuration, and
 abort.</para></note>
 <section xml:id="sec-nix-ssl-cert-file-with-nix-daemon-and-macos">
 <title><envar>NIX_SSL_CERT_FILE</envar> with macOS and the Nix daemon</title>
 <para>On macOS you must specify the environment variable for the Nix
 daemon service, then restart it:</para>
 <screen>
 $ sudo launchctl setenv NIX_SSL_CERT_FILE /etc/ssl/my-certificate-bundle.crt
 $ sudo launchctl kickstart -k system/org.nixos.nix-daemon
 </screen>
 </section>
 </section>
 </chapter>
--- a/doc/manual/installation/installation.xml
+++ b/doc/manual/installation/installation.xml
@ -1,34 +0,0 @@
 <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>
--- a/doc/manual/installation/installing-binary.xml
+++ b/doc/manual/installation/installing-binary.xml
@ -1,190 +0,0 @@
 <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 macOS, the easiest way to install Nix
 is to run the following command:
 <screen>
  $ sh &lt;(curl https://nixos.org/nix/install)
 </screen>
 As of Nix 2.1.0, the Nix installer will always default to creating a
 single-user installation, however opting in to the multi-user
 installation is highly recommended.
 </para>
 <section xml:id="sect-single-user-installation">
  <title>Single User Installation</title>
  <para>
    To explicitly select a single-user installation on your system:
    <screen>
  sh &lt;(curl https://nixos.org/nix/install) --no-daemon
 </screen>
  </para>
 <para>
 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 uninstall Nix simply by running:
 <screen>
 $ rm -rf /nix
 </screen>
 </para>
 </section>
 <section xml:id="sect-multi-user-installation">
  <title>Multi User Installation</title>
  <para>
    The multi-user Nix installation creates system users, and a system
    service for the Nix daemon.
  </para>
  <itemizedlist>
    <title>Supported Systems</title>
    <listitem>
      <para>Linux running systemd, with SELinux disabled</para>
    </listitem>
    <listitem><para>macOS</para></listitem>
  </itemizedlist>
  <para>
    You can instruct the installer to perform a multi-user
    installation on your system:
    <screen>
  sh &lt;(curl https://nixos.org/nix/install) --daemon
 </screen>
  </para>
  <para>
    The multi-user installation of Nix will create build users between
    the user IDs 30001 and 30032, and a group with the group ID 30000.
    You should run this under your usual user account,
    <emphasis>not</emphasis> as root. The script will invoke
    <command>sudo</command> as needed.
  </para>
  <note><para>
    If you need Nix to use a different group ID or user ID set, you
    will have to download the tarball manually and <link
    linkend="sect-nix-install-binary-tarball">edit the install
    script</link>.
  </para></note>
  <para>
    The installer will modify <filename>/etc/bashrc</filename>, and
    <filename>/etc/zshrc</filename> if they exist. The installer will
    first back up these files with a
    <literal>.backup-before-nix</literal> extension. The installer
    will also create <filename>/etc/profile.d/nix.sh</filename>.
  </para>
  <para>You can uninstall Nix with the following commands:
 <screen>
 sudo rm -rf /etc/profile/nix.sh /etc/nix /nix ~root/.nix-profile ~root/.nix-defexpr ~root/.nix-channels ~/.nix-profile ~/.nix-defexpr ~/.nix-channels
 # If you are on Linux with systemd, you will need to run:
 sudo systemctl stop nix-daemon.socket
 sudo systemctl stop nix-daemon.service
 sudo systemctl disable nix-daemon.socket
 sudo systemctl disable nix-daemon.service
 sudo systemctl daemon-reload
 # If you are on macOS, you will need to run:
 sudo launchctl unload /Library/LaunchDaemons/org.nixos.nix-daemon.plist
 sudo rm /Library/LaunchDaemons/org.nixos.nix-daemon.plist
 </screen>
    There may also be references to Nix in
    <filename>/etc/profile</filename>,
    <filename>/etc/bashrc</filename>, and
    <filename>/etc/zshrc</filename> which you may remove.
  </para>
 </section>
 <section xml:id="sect-nix-install-pinned-version-url">
  <title>Installing a pinned Nix version from a URL</title>
  <para>
    NixOS.org hosts version-specific installation URLs for all Nix
    versions since 1.11.16, at
    <literal>https://nixos.org/releases/nix/nix-VERSION/install</literal>.
  </para>
  <para>
    These install scripts can be used the same as the main
  NixOS.org installation script:
  <screen>
  sh &lt;(curl https://nixos.org/nix/install)
 </screen>
  </para>
  <para>
    In the same directory of the install script are sha256 sums, and
    gpg signature files.
  </para>
 </section>
 <section xml:id="sect-nix-install-binary-tarball">
  <title>Installing from a binary tarball</title>
  <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>
    If you need to edit the multi-user installation script to use
    different group ID or a different user ID range, modify the
    variables set in the file named
    <filename>install-multi-user</filename>.
  </para>
 </section>
 </chapter>
--- a/doc/manual/installation/installing-source.xml
+++ b/doc/manual/installation/installing-source.xml
@ -1,16 +0,0 @@
 <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>
--- a/doc/manual/installation/multi-user.xml
+++ b/doc/manual/installation/multi-user.xml
@ -1,107 +0,0 @@
 <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>
 </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>
--- a/doc/manual/installation/nix-security.xml
+++ b/doc/manual/installation/nix-security.xml
@ -1,27 +0,0 @@
 <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>
--- a/doc/manual/installation/obtaining-source.xml
+++ b/doc/manual/installation/obtaining-source.xml
@ -1,30 +0,0 @@
 <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>
--- a/doc/manual/installation/prerequisites-source.xml
+++ b/doc/manual/installation/prerequisites-source.xml
@ -1,101 +0,0 @@
 <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>Bash Shell. The <literal>./configure</literal> script
  relies on bashisms, so Bash is required.</para></listitem>
  <listitem><para>A version of GCC or Clang that supports C++14.</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 <literal>libbrotlienc</literal> and
  <literal>libbrotlidec</literal> libraries to provide implementation
  of the Brotli compression algorithm. They are available for download
  from the official repository <link
  xlink:href="https://github.com/google/brotli" />.</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="https://web.archive.org/web/20180624184756/http://www.bzip.org/"
  />.</para></listitem>
  <listitem><para><literal>liblzma</literal>, which is provided by
  XZ Utils. If your distribution does not provide this, you can
  get it from <link xlink:href="https://tukaani.org/xz/"/>.</para></listitem>
  <listitem><para>cURL and its library. If your distribution does not
  provide it, you can get it from <link
  xlink:href="https://curl.haxx.se/"/>.</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 <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 <literal>boost</literal> library of version
  1.66.0 or higher. It can be obtained from the official web site
  <link xlink:href="https://www.boost.org/" />.</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>
  <listitem><para>The <literal>libseccomp</literal> is used to provide
  syscall filtering on Linux. This is an optional dependency and can
  be disabled passing a <option>--disable-seccomp-sandboxing</option>
  option to the <command>configure</command> script (Not recommended
  unless your system doesn't support
  <literal>libseccomp</literal>). To get the library, visit <link
  xlink:href="https://github.com/seccomp/libseccomp"
  />.</para></listitem>
 </itemizedlist>
 </section>
--- a/doc/manual/installation/single-user.xml
+++ b/doc/manual/installation/single-user.xml
@ -1,21 +0,0 @@
 <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>
--- a/doc/manual/installation/supported-platforms.xml
+++ b/doc/manual/installation/supported-platforms.xml
@ -1,36 +0,0 @@
 <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, aarch64).</para></listitem>
  <listitem><para>macOS (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>
 </chapter>
--- a/doc/manual/installation/upgrading.xml
+++ b/doc/manual/installation/upgrading.xml
@ -1,22 +0,0 @@
 <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-upgrading-nix">
  <title>Upgrading Nix</title>
  <para>
    Multi-user Nix users on macOS can upgrade Nix by running:
    <command>sudo -i sh -c 'nix-channel --update &amp;&amp;
    nix-env -iA nixpkgs.nix &amp;&amp;
    launchctl remove org.nixos.nix-daemon &amp;&amp;
    launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist'</command>
  </para>
  <para>
    Single-user installations of Nix should run this:
    <command>nix-channel --update; nix-env -iA nixpkgs.nix</command>
  </para>
 </chapter>
--- a/doc/manual/introduction/about-nix.xml
+++ b/doc/manual/introduction/about-nix.xml
@ -1,268 +0,0 @@
 <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-about-nix">
 <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
 programming languages such as Haskell — they are built by functions
 that don’t have side-effects, and they never change after they have
 been built.  Nix stores packages in the <emphasis>Nix
 store</emphasis>, usually the directory
 <filename>/nix/store</filename>, where each package has its own unique
 subdirectory such as
 <programlisting>
 /nix/store/b6gvzjyb2pg0kjfwrjmg1vfhh54ad73z-firefox-33.1/
 </programlisting>
 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>
 <simplesect><title>Multiple versions</title>
 <para>You can have multiple versions or variants of a package
 installed at the same time.  This is especially important when
 different applications have dependencies on different versions of the
 same package — it prevents the “DLL hell”.  Because of the hashing
 scheme, different versions of a package end up in different paths in
 the Nix store, so they don’t interfere with each other.</para>
 <para>An important consequence is that operations like upgrading or
 uninstalling an application cannot break other applications, since
 these operations never “destructively” update or delete files that are
 used by other packages.</para>
 </simplesect>
 <simplesect><title>Complete dependencies</title>
 <para>Nix helps you make sure that package dependency specifications
 are complete.  In general, when you’re making a package for a package
 management system like RPM, you have to specify for each package what
 its dependencies are, but there are no guarantees that this
 specification is complete.  If you forget a dependency, then the
 package will build and work correctly on <emphasis>your</emphasis>
 machine if you have the dependency installed, but not on the end
 user's machine if it's not there.</para>
 <para>Since Nix on the other hand doesn’t install packages in “global”
 locations like <filename>/usr/bin</filename> but in package-specific
 directories, the risk of incomplete dependencies is greatly reduced.
 This is because tools such as compilers don’t search in per-packages
 directories such as
 <filename>/nix/store/5lbfaxb722zp…-openssl-0.9.8d/include</filename>,
 so if a package builds correctly on your system, this is because you
 specified the dependency explicitly. This takes care of the build-time
 dependencies.</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>
 <simplesect><title>Multi-user support</title>
 <para>Nix has multi-user support.  This means that non-privileged
 users can securely install software.  Each user can have a different
 <emphasis>profile</emphasis>, a set of packages in the Nix store that
 appear in the user’s <envar>PATH</envar>.  If a user installs a
 package that another user has already installed previously, the
 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>
 </simplesect>
 <simplesect><title>Atomic upgrades and rollbacks</title>
 <para>Since package management operations never overwrite packages in
 the Nix store but just add new versions in different paths, they are
 <emphasis>atomic</emphasis>.  So during a package upgrade, there is no
 time window in which the package has some files from the old version
 and some files from the new version — which would be bad because a
 program might well crash if it’s started during that period.</para>
 <para>And since packages aren’t overwritten, the old versions are still
 there after an upgrade.  This means that you can <emphasis>roll
 back</emphasis> to the old version:</para>
 <screen>
 $ nix-env --upgrade <replaceable>some-packages</replaceable>
 $ nix-env --rollback
 </screen>
 </simplesect>
 <simplesect><title>Garbage collection</title>
 <para>When you uninstall a package like this…
 <screen>
 $ nix-env --uninstall firefox
 </screen>
 the package isn’t deleted from the system right away (after all, you
 might want to do a rollback, or it might be in the profiles of other
 users).  Instead, unused packages can be deleted safely by running the
 <emphasis>garbage collector</emphasis>:
 <screen>
 $ nix-collect-garbage
 </screen>
 This deletes all packages that aren’t in use by any user profile or by
 a currently running program.</para>
 </simplesect>
 <simplesect><title>Functional package language</title>
 <para>Packages are built from <emphasis>Nix expressions</emphasis>,
 which is a simple functional language.  A Nix expression describes
 everything that goes into a package build action (a “derivation”):
 other packages, sources, the build script, environment variables for
 the build script, etc.  Nix tries very hard to ensure that Nix
 expressions are <emphasis>deterministic</emphasis>: building a Nix
 expression twice should yield the same result.</para>
 <para>Because it’s a functional language, it’s easy to support
 building variants of a package: turn the Nix expression into a
 function and call it any number of times with the appropriate
 arguments.  Due to the hashing scheme, variants don’t conflict with
 each other in the Nix store.</para>
 </simplesect>
 <simplesect><title>Transparent source/binary deployment</title>
 <para>Nix expressions generally describe how to build a package from
 source, so an installation action like
 <screen>
 $ nix-env --install firefox
 </screen>
 <emphasis>could</emphasis> cause quite a bit of build activity, as not
 only Firefox but also all its dependencies (all the way up to the C
 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 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
 available, Nix can download binary deltas that patch an existing
 package in the Nix store into a new version.  This speeds up
 upgrades.</para>
 </simplesect>
 -->
 <simplesect><title>Nix Packages collection</title>
 <para>We provide a large set of Nix expressions containing hundreds of
 existing Unix packages, the <emphasis>Nix Packages
 collection</emphasis> (Nixpkgs).</para>
 </simplesect>
 <simplesect><title>Managing build environments</title>
 <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>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>
 <simplesect><title>Portability</title>
 <para>Nix runs on Linux and macOS.</para>
 </simplesect>
 <simplesect><title>NixOS</title>
 <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
 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>
 <simplesect><title>License</title>
 <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>
 </simplesect>
 </chapter>
--- a/doc/manual/introduction/introduction.xml
+++ b/doc/manual/introduction/introduction.xml
@ -1,12 +0,0 @@
 <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>
--- a/doc/manual/introduction/quick-start.xml
+++ b/doc/manual/introduction/quick-start.xml
@ -1,124 +0,0 @@
 <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="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 subsequent chapters.</para>
 <procedure>
 <step><para>Install single-user Nix by running the following:
 <screen>
 $ bash &lt;(curl https://nixos.org/nix/install)
 </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></step>
 <step><para>See what installable packages are currently available
 in the channel:
 <screen>
 $ nix-env -qa
 docbook-xml-4.3
 docbook-xml-4.5
 firefox-33.0.2
 hello-2.9
 libxslt-1.1.28
 <replaceable>...</replaceable></screen>
 </para></step>
 <step><para>Install some packages from the channel:
 <screen>
 $ nix-env -i hello</screen>
 This should download pre-built packages; it should not build them
 locally (if it does, something went wrong).</para></step>
 <step><para>Test that they work:
 <screen>
 $ which hello
 /home/eelco/.nix-profile/bin/hello
 $ hello
 Hello, world!
 </screen>
 </para></step>
 <step><para>Uninstall a package:
 <screen>
 $ nix-env -e hello</screen>
 </para></step>
 <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
 $ 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></step>
 <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></step>
 <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:
 <screen>
 $ nix-collect-garbage -d</screen>
 <!--
 The first command deletes old “generations” of your profile (making
 rollbacks impossible, but also making the packages in those old
 generations available for garbage collection), while the second
 command actually deletes them.-->
 </para></step>
 </procedure>
 </chapter>
--- a/doc/manual/local.mk
+++ b/doc/manual/local.mk
@ -1,43 +1,6 @@
 ifeq ($(doc_generate),yes)
-XSLTPROC = $(xsltproc) --nonet $(xmlflags) \
+MANUAL_SRCS := $(call rwildcard, $(d)/src, *.md)
  --param section.autolabel 1 \
  --param section.label.includes.component.label 1 \
  --param html.stylesheet \'style.css\' \
  --param xref.with.number.and.title 1 \
  --param toc.section.depth 3 \
  --param admon.style \'\' \
  --param callout.graphics.extension \'.gif\' \
  --param contrib.inline.enabled 0 \
  --stringparam generate.toc "book toc" \
  --param keep.relative.image.uris 0
 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
 $(d)/manual.xmli: $(d)/manual.xml $(MANUAL_SRCS) $(d)/version.txt
 	$(trace-gen) $(xmllint) --nonet --xinclude $< -o $@.tmp
 	@mv $@.tmp $@
 $(d)/version.txt:
 	$(trace-gen) echo -n $(PACKAGE_VERSION) > $@
 # Note: RelaxNG validation requires xmllint >= 2.7.4.
 $(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) -
 	@touch $@
 clean-files += $(d)/manual.xmli $(d)/version.txt $(d)/manual.is-valid
 dist-files += $(d)/manual.xmli $(d)/version.txt $(d)/manual.is-valid
 # Generate man pages.
 man-pages := $(foreach n, \
@ -48,40 +11,80 @@ man-pages := $(foreach n, \
  nix.conf.5 nix-daemon.8, \
  $(d)/$(n))
 $(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)
+# Provide a dummy environment for nix, so that it will not access files outside the macOS sandbox.
 dummy-env = env -i \
 	HOME=/dummy \
 	NIX_CONF_DIR=/dummy \
 	NIX_SSL_CERT_FILE=/dummy/no-ca-bundle.crt \
 	NIX_STATE_DIR=/dummy
 nix-eval = $(dummy-env) $(bindir)/nix eval --experimental-features nix-command -I nix/corepkgs=corepkgs --store dummy:// --impure --raw
 $(d)/%.1: $(d)/src/command-ref/%.md
 	@printf "Title: %s\n\n" "$$(basename $@ .1)" > $^.tmp
 	@cat $^ >> $^.tmp
 	$(trace-gen) lowdown -sT man $^.tmp -o $@
 	@rm $^.tmp
 $(d)/%.8: $(d)/src/command-ref/%.md
 	@printf "Title: %s\n\n" "$$(basename $@ .8)" > $^.tmp
 	@cat $^ >> $^.tmp
 	$(trace-gen) lowdown -sT man $^.tmp -o $@
 	@rm $^.tmp
 $(d)/nix.conf.5: $(d)/src/command-ref/conf-file.md
 	@printf "Title: %s\n\n" "$$(basename $@ .5)" > $^.tmp
 	@cat $^ >> $^.tmp
 	$(trace-gen) lowdown -sT man $^.tmp -o $@
 	@rm $^.tmp
 $(d)/src/SUMMARY.md: $(d)/src/SUMMARY.md.in $(d)/src/command-ref/new-cli
 	$(trace-gen) cat doc/manual/src/SUMMARY.md.in | while IFS= read line; do if [[ $$line = @manpages@ ]]; then cat doc/manual/src/command-ref/new-cli/SUMMARY.md; else echo "$$line"; fi; done > $@.tmp
 	@mv $@.tmp $@
 $(d)/src/command-ref/new-cli: $(d)/nix.json $(d)/generate-manpage.nix $(bindir)/nix
 	@rm -rf $@
 	$(trace-gen) $(nix-eval) --write-to $@ --expr 'import doc/manual/generate-manpage.nix (builtins.fromJSON (builtins.readFile $<))'
 $(d)/src/command-ref/conf-file.md: $(d)/conf-file.json $(d)/generate-options.nix $(d)/src/command-ref/conf-file-prefix.md $(bindir)/nix
 	@cat doc/manual/src/command-ref/conf-file-prefix.md > $@.tmp
 	$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-options.nix (builtins.fromJSON (builtins.readFile $<))' >> $@.tmp
 	@mv $@.tmp $@
 $(d)/nix.json: $(bindir)/nix
 	$(trace-gen) $(dummy-env) $(bindir)/nix __dump-args > $@.tmp
 	@mv $@.tmp $@
 $(d)/conf-file.json: $(bindir)/nix
 	$(trace-gen) $(dummy-env) $(bindir)/nix show-config --json --experimental-features nix-command > $@.tmp
 	@mv $@.tmp $@
 $(d)/src/expressions/builtins.md: $(d)/builtins.json $(d)/generate-builtins.nix $(d)/src/expressions/builtins-prefix.md $(bindir)/nix
 	@cat doc/manual/src/expressions/builtins-prefix.md > $@.tmp
 	$(trace-gen) $(nix-eval) --expr 'import doc/manual/generate-builtins.nix (builtins.fromJSON (builtins.readFile $<))' >> $@.tmp
 	@mv $@.tmp $@
 $(d)/builtins.json: $(bindir)/nix
 	$(trace-gen) $(dummy-env) NIX_PATH=nix/corepkgs=corepkgs $(bindir)/nix __dump-builtins > $@.tmp
 	@mv $@.tmp $@
 # Generate the HTML manual.
-$(d)/manual.html: $(d)/manual.xml $(MANUAL_SRCS) $(d)/manual.is-valid
+install: $(docdir)/manual/index.html
 	$(trace-gen) $(XSLTPROC) --xinclude --stringparam profile.condition manual \
 	  $(docbookxsl)/profiling/profile.xsl $< | \
 	  $(XSLTPROC) --output $@ $(docbookxsl)/xhtml/docbook.xsl -
-$(foreach file, $(d)/manual.html $(d)/style.css, $(eval $(call install-data-in, $(file), $(docdir)/manual)))
+# Generate 'nix' manpages.
-
+install: $(d)/src/command-ref/new-cli
-$(foreach file, $(wildcard $(d)/figures/*.png), $(eval $(call install-data-in, $(file), $(docdir)/manual/figures)))
+	$(trace-gen) for i in doc/manual/src/command-ref/new-cli/*.md; do \
-
+	  name=$$(basename $$i .md); \
-$(foreach file, $(wildcard $(d)/images/callouts/*.gif), $(eval $(call install-data-in, $(file), $(docdir)/manual/images/callouts)))
+	  if [[ $$name = SUMMARY ]]; then continue; fi; \
-
+	  printf "Title: %s\n\n" "$$name" > $$i.tmp; \
-$(eval $(call install-symlink, manual.html, $(docdir)/manual/index.html))
+	  cat $$i >> $$i.tmp; \
-
+	  lowdown -sT man $$i.tmp -o $(mandir)/man1/$$name.1; \
-
+	done
 all: $(d)/manual.html
 clean-files += $(d)/manual.html
 dist-files += $(d)/manual.html
 $(docdir)/manual/index.html: $(MANUAL_SRCS) $(d)/book.toml $(d)/custom.css $(d)/src/SUMMARY.md $(d)/src/command-ref/new-cli $(d)/src/command-ref/conf-file.md $(d)/src/expressions/builtins.md
 	$(trace-gen) RUST_LOG=warn mdbook build doc/manual -d $(docdir)/manual
 	@cp doc/manual/highlight.pack.js $(docdir)/manual/highlight.js
 endif
--- a/doc/manual/manual.xml
+++ b/doc/manual/manual.xml
@ -1,52 +0,0 @@
 <book 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">
  <info>
    <title>Nix Package Manager Guide</title>
    <subtitle>Version <xi:include href="version.txt" parse="text" /></subtitle>
    <author>
      <personname>
        <firstname>Eelco</firstname>
        <surname>Dolstra</surname>
      </personname>
      <contrib>Author</contrib>
    </author>
    <copyright>
      <year>2004-2018</year>
      <holder>Eelco Dolstra</holder>
    </copyright>
  </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/introduction.xml" />
  <xi:include href="installation/installation.xml" />
  <xi:include href="installation/upgrading.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="glossary/glossary.xml" />
  <xi:include href="hacking.xml" />
  <xi:include href="release-notes/release-notes.xml" />
 <!--
 <appendix>
    <title>Nix Release Notes</title>
    <xi:include href="release-notes/release-notes.xml"
                xpointer="xmlns(x=http://docbook.org/ns/docbook)xpointer(x:article/x:section)" />
  </appendix>
 -->
 </book>
--- a/doc/manual/nix-lang-ref.xml
+++ b/doc/manual/nix-lang-ref.xml
@ -1,182 +0,0 @@
 <appendix>
  <title>Nix Language Reference</title>
  <sect1>
    <title>Grammar</title>
    <productionset>
      <title>Expressions</title>
      <production id="nix.expr">
        <lhs>Expr</lhs>
        <rhs>
          <nonterminal def="#nix.expr_function" />
        </rhs>
      </production>
      <production id="nix.expr_function">
        <lhs>ExprFunction</lhs>
        <rhs>
          '{' <nonterminal def="#nix.formals" /> '}' ':' <nonterminal def="#nix.expr_function" />
          <sbr />|
          <nonterminal def="#nix.expr_assert" />
        </rhs>
      </production>
      <production id="nix.expr_assert">
        <lhs>ExprAssert</lhs>
        <rhs>
          'assert' <nonterminal def="#nix.expr" /> ';' <nonterminal def="#nix.expr_assert" />
          <sbr />|
          <nonterminal def="#nix.expr_if" />
        </rhs>
      </production>
      <production id="nix.expr_if">
        <lhs>ExprIf</lhs>
        <rhs>
          'if' <nonterminal def="#nix.expr" /> 'then' <nonterminal def="#nix.expr" />
          'else' <nonterminal def="#nix.expr" />
          <sbr />|
          <nonterminal def="#nix.expr_op" />
        </rhs>
      </production>
      <production id="nix.expr_op">
        <lhs>ExprOp</lhs>
        <rhs>
          '!' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '==' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '!=' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '&amp;&amp;' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '||' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '->' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '//' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '~' <nonterminal def="#nix.expr_op" />
          <sbr />|
          <nonterminal def="#nix.expr_op" /> '?' <nonterminal def="#nix.id" />
          <sbr />|
          <nonterminal def="#nix.expr_app" />
        </rhs>
      </production>
      <production id="nix.expr_app">
        <lhs>ExprApp</lhs>
        <rhs>
          <nonterminal def="#nix.expr_app" /> '.' <nonterminal def="#nix.expr_select" />
          <sbr />|
          <nonterminal def="#nix.expr_select" />
        </rhs>
      </production>
      <production id="nix.expr_select">
        <lhs>ExprSelect</lhs>
        <rhs>
          <nonterminal def="#nix.expr_select" /> <nonterminal def="#nix.id" />
          <sbr />|
          <nonterminal def="#nix.expr_simple" />
        </rhs>
      </production>
      <production id="nix.expr_simple">
        <lhs>ExprSimple</lhs>
        <rhs>
          <nonterminal def="#nix.id" /> |
          <nonterminal def="#nix.int" /> |
          <nonterminal def="#nix.str" /> |
          <nonterminal def="#nix.path" /> |
          <nonterminal def="#nix.uri" />
          <sbr />|
          'true' | 'false' | 'null'
          <sbr />|
          '(' <nonterminal def="#nix.expr" /> ')'
          <sbr />|
          '{' <nonterminal def="#nix.bind" />* '}'
          <sbr />|
          'let' '{' <nonterminal def="#nix.bind" />* '}'
          <sbr />|
          'rec' '{' <nonterminal def="#nix.bind" />* '}'
          <sbr />|
          '[' <nonterminal def="#nix.expr_select" />* ']'
        </rhs>
      </production>
      <production id="nix.bind">
        <lhs>Bind</lhs>
        <rhs>
          <nonterminal def="#nix.id" /> '=' <nonterminal def="#nix.expr" /> ';'
          <sbr />|
          'inherit' ('(' <nonterminal def="#nix.expr" /> ')')? <nonterminal def="#nix.id" />* ';'
        </rhs>
      </production>
      <production id="nix.formals">
        <lhs>Formals</lhs>
        <rhs>
          <nonterminal def="#nix.formal" /> ',' <nonterminal def="#nix.formals" />
          | <nonterminal def="#nix.formal" />
        </rhs>
      </production>
      <production id="nix.formal">
        <lhs>Formal</lhs>
        <rhs>
          <nonterminal def="#nix.id" />
          <sbr />|
          <nonterminal def="#nix.id" /> '?' <nonterminal def="#nix.expr" />
        </rhs>
      </production>
    </productionset>
    <productionset>
      <title>Terminals</title>
      <production id="nix.id">
        <lhs>Id</lhs>
        <rhs>[a-zA-Z\_][a-zA-Z0-9\_\']*</rhs>
      </production>
      <production id="nix.int">
        <lhs>Int</lhs>
        <rhs>[0-9]+</rhs>
      </production>
      <production id="nix.str">
        <lhs>Str</lhs>
        <rhs>\"[^\n\"]*\"</rhs>
      </production>
      <production id="nix.path">
        <lhs>Path</lhs>
        <rhs>[a-zA-Z0-9\.\_\-\+]*(\/[a-zA-Z0-9\.\_\-\+]+)+</rhs>
      </production>
      <production id="nix.uri">
        <lhs>Uri</lhs>
        <rhs>[a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&amp;\=\+\$\,\-\_\.\!\~\*\']+</rhs>
      </production>
      <production id="nix.ws">
        <lhs>Whitespace</lhs>
        <rhs>
          [ \t\n]+
          <sbr />|
          \#[^\n]*
          <sbr />|
          \/\*(.|\n)*\*\/
        </rhs>
      </production>
    </productionset>
  </sect1>
 </appendix>
--- a/doc/manual/packages/basic-package-mgmt.xml
+++ b/doc/manual/packages/basic-package-mgmt.xml
@ -1,194 +0,0 @@
 <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>
--- a/doc/manual/packages/binary-cache-substituter.xml
+++ b/doc/manual/packages/binary-cache-substituter.xml
@ -1,70 +0,0 @@
 <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>
--- a/Show more
+++ b/Show more
		`@ -1,2 +0,0 @@`
			`os: osx`
			`script: ./tests/install-darwin.sh`
		`@ -0,0 +1,2 @@`
							`[output.html]`
							`additional-css = ["custom.css"]`