Merge pull request #47688 from grahamc/doc-breakout-functions

nixpkgs docs: breakout functions

11 files changed, 1102 insertions, 1065 deletions

diff --git a/doc/Makefile b/doc/Makefile
index ba77be6678c4..173e1c0b19ee 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -69,7 +69,7 @@ highlightjs:
 	cp -r "$$HIGHLIGHTJS/loader.js" highlightjs/
 
 
-manual-full.xml: ${MD_TARGETS} .version *.xml
+manual-full.xml: ${MD_TARGETS} .version *.xml **/*.xml
 	xmllint --nonet --xinclude --noxincludenode manual.xml --output manual-full.xml
 
 .version:
diff --git a/doc/cross-compilation.xml b/doc/cross-compilation.xml
index c7187d86d1b3..da664394f262 100644
--- a/doc/cross-compilation.xml
+++ b/doc/cross-compilation.xml
@@ -47,9 +47,10 @@
 
    <para>
     In Nixpkgs, these three platforms are defined as attribute sets under the
-    names <literal>buildPlatform</literal>, <literal>hostPlatform</literal>, and
-    <literal>targetPlatform</literal>. They are always defined as attributes in
-    the standard environment. That means one can access them like:
+    names <literal>buildPlatform</literal>, <literal>hostPlatform</literal>,
+    and <literal>targetPlatform</literal>. They are always defined as
+    attributes in the standard environment. That means one can access them
+    like:
 <programlisting>{ stdenv, fooDep, barDep, .. }: ...stdenv.buildPlatform...</programlisting>
     .
    </para>
diff --git a/doc/functions.xml b/doc/functions.xml
index 8223a8b0531c..88011061ae6e 100644
--- a/doc/functions.xml
+++ b/doc/functions.xml
@@ -7,1016 +7,11 @@
   The nixpkgs repository has several utility functions to manipulate Nix
   expressions.
  </para>
- <section xml:id="sec-overrides">
-  <title>Overriding</title>
 
-  <para>
-   Sometimes one wants to override parts of <literal>nixpkgs</literal>, e.g.
-   derivation attributes, the results of derivations or even the whole package
-   set.
-  </para>
-
-  <section xml:id="sec-pkg-override">
-   <title>&lt;pkg&gt;.override</title>
-
-   <para>
-    The function <varname>override</varname> is usually available for all the
-    derivations in the nixpkgs expression (<varname>pkgs</varname>).
-   </para>
-
-   <para>
-    It is used to override the arguments passed to a function.
-   </para>
-
-   <para>
-    Example usages:
-<programlisting>pkgs.foo.override { arg1 = val1; arg2 = val2; ... }</programlisting>
-<programlisting>
-import pkgs.path { overlays = [ (self: super: {
-  foo = super.foo.override { barSupport = true ; };
-  })]};
-</programlisting>
-<programlisting>
-mypkg = pkgs.callPackage ./mypkg.nix {
-  mydep = pkgs.mydep.override { ... };
-  }
-</programlisting>
-   </para>
-
-   <para>
-    In the first example, <varname>pkgs.foo</varname> is the result of a
-    function call with some default arguments, usually a derivation. Using
-    <varname>pkgs.foo.override</varname> will call the same function with the
-    given new arguments.
-   </para>
-  </section>
-
-  <section xml:id="sec-pkg-overrideAttrs">
-   <title>&lt;pkg&gt;.overrideAttrs</title>
-
-   <para>
-    The function <varname>overrideAttrs</varname> allows overriding the
-    attribute set passed to a <varname>stdenv.mkDerivation</varname> call,
-    producing a new derivation based on the original one. This function is
-    available on all derivations produced by the
-    <varname>stdenv.mkDerivation</varname> function, which is most packages in
-    the nixpkgs expression <varname>pkgs</varname>.
-   </para>
-
-   <para>
-    Example usage:
-<programlisting>
-helloWithDebug = pkgs.hello.overrideAttrs (oldAttrs: rec {
-  separateDebugInfo = true;
-});
-</programlisting>
-   </para>
-
-   <para>
-    In the above example, the <varname>separateDebugInfo</varname> attribute is
-    overridden to be true, thus building debug info for
-    <varname>helloWithDebug</varname>, while all other attributes will be
-    retained from the original <varname>hello</varname> package.
-   </para>
-
-   <para>
-    The argument <varname>oldAttrs</varname> is conventionally used to refer to
-    the attr set originally passed to <varname>stdenv.mkDerivation</varname>.
-   </para>
-
-   <note>
-    <para>
-     Note that <varname>separateDebugInfo</varname> is processed only by the
-     <varname>stdenv.mkDerivation</varname> function, not the generated, raw
-     Nix derivation. Thus, using <varname>overrideDerivation</varname> will not
-     work in this case, as it overrides only the attributes of the final
-     derivation. It is for this reason that <varname>overrideAttrs</varname>
-     should be preferred in (almost) all cases to
-     <varname>overrideDerivation</varname>, i.e. to allow using
-     <varname>sdenv.mkDerivation</varname> to process input arguments, as well
-     as the fact that it is easier to use (you can use the same attribute names
-     you see in your Nix code, instead of the ones generated (e.g.
-     <varname>buildInputs</varname> vs <varname>nativeBuildInputs</varname>,
-     and involves less typing.
-    </para>
-   </note>
-  </section>
-
-  <section xml:id="sec-pkg-overrideDerivation">
-   <title>&lt;pkg&gt;.overrideDerivation</title>
-
-   <warning>
-    <para>
-     You should prefer <varname>overrideAttrs</varname> in almost all cases,
-     see its documentation for the reasons why.
-     <varname>overrideDerivation</varname> is not deprecated and will continue
-     to work, but is less nice to use and does not have as many abilities as
-     <varname>overrideAttrs</varname>.
-    </para>
-   </warning>
-
-   <warning>
-    <para>
-     Do not use this function in Nixpkgs as it evaluates a Derivation before
-     modifying it, which breaks package abstraction and removes error-checking
-     of function arguments. In addition, this evaluation-per-function
-     application incurs a performance penalty, which can become a problem if
-     many overrides are used. It is only intended for ad-hoc customisation,
-     such as in <filename>~/.config/nixpkgs/config.nix</filename>.
-    </para>
-   </warning>
-
-   <para>
-    The function <varname>overrideDerivation</varname> creates a new derivation
-    based on an existing one by overriding the original's attributes with the
-    attribute set produced by the specified function. This function is
-    available on all derivations defined using the
-    <varname>makeOverridable</varname> function. Most standard
-    derivation-producing functions, such as
-    <varname>stdenv.mkDerivation</varname>, are defined using this function,
-    which means most packages in the nixpkgs expression,
-    <varname>pkgs</varname>, have this function.
-   </para>
-
-   <para>
-    Example usage:
-<programlisting>
-mySed = pkgs.gnused.overrideDerivation (oldAttrs: {
-  name = "sed-4.2.2-pre";
-  src = fetchurl {
-    url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
-    sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
-  };
-  patches = [];
-});
-</programlisting>
-   </para>
-
-   <para>
-    In the above example, the <varname>name</varname>, <varname>src</varname>,
-    and <varname>patches</varname> of the derivation will be overridden, while
-    all other attributes will be retained from the original derivation.
-   </para>
-
-   <para>
-    The argument <varname>oldAttrs</varname> is used to refer to the attribute
-    set of the original derivation.
-   </para>
-
-   <note>
-    <para>
-     A package's attributes are evaluated *before* being modified by the
-     <varname>overrideDerivation</varname> function. For example, the
-     <varname>name</varname> attribute reference in <varname>url =
-     "mirror://gnu/hello/${name}.tar.gz";</varname> is filled-in *before* the
-     <varname>overrideDerivation</varname> function modifies the attribute set.
-     This means that overriding the <varname>name</varname> attribute, in this
-     example, *will not* change the value of the <varname>url</varname>
-     attribute. Instead, we need to override both the <varname>name</varname>
-     *and* <varname>url</varname> attributes.
-    </para>
-   </note>
-  </section>
-
-  <section xml:id="sec-lib-makeOverridable">
-   <title>lib.makeOverridable</title>
-
-   <para>
-    The function <varname>lib.makeOverridable</varname> is used to make the
-    result of a function easily customizable. This utility only makes sense for
-    functions that accept an argument set and return an attribute set.
-   </para>
-
-   <para>
-    Example usage:
-<programlisting>
-f = { a, b }: { result = a+b; };
-c = lib.makeOverridable f { a = 1; b = 2; };
-</programlisting>
-   </para>
-
-   <para>
-    The variable <varname>c</varname> is the value of the <varname>f</varname>
-    function applied with some default arguments. Hence the value of
-    <varname>c.result</varname> is <literal>3</literal>, in this example.
-   </para>
-
-   <para>
-    The variable <varname>c</varname> however also has some additional
-    functions, like <link linkend="sec-pkg-override">c.override</link> which
-    can be used to override the default arguments. In this example the value of
-    <varname>(c.override { a = 4; }).result</varname> is 6.
-   </para>
-  </section>
- </section>
- <section xml:id="sec-generators">
-  <title>Generators</title>
-
-  <para>
-   Generators are functions that create file formats from nix data structures,
-   e. g. for configuration files. There are generators available for:
-   <literal>INI</literal>, <literal>JSON</literal> and <literal>YAML</literal>
-  </para>
-
-  <para>
-   All generators follow a similar call interface: <code>generatorName
-   configFunctions data</code>, where <literal>configFunctions</literal> is an
-   attrset of user-defined functions that format nested parts of the content.
-   They each have common defaults, so often they do not need to be set
-   manually. An example is <code>mkSectionName ? (name: libStr.escape [ "[" "]"
-   ] name)</code> from the <literal>INI</literal> generator. It receives the
-   name of a section and sanitizes it. The default
-   <literal>mkSectionName</literal> escapes <literal>[</literal> and
-   <literal>]</literal> with a backslash.
-  </para>
-
-  <para>
-   Generators can be fine-tuned to produce exactly the file format required by
-   your application/service. One example is an INI-file format which uses
-   <literal>: </literal> as separator, the strings
-   <literal>"yes"</literal>/<literal>"no"</literal> as boolean values and
-   requires all string values to be quoted:
-  </para>
-
-<programlisting>
-with lib;
-let
-  customToINI = generators.toINI {
-    # specifies how to format a key/value pair
-    mkKeyValue = generators.mkKeyValueDefault {
-      # specifies the generated string for a subset of nix values
-      mkValueString = v:
-             if v == true then ''"yes"''
-        else if v == false then ''"no"''
-        else if isString v then ''"${v}"''
-        # and delegats all other values to the default generator
-        else generators.mkValueStringDefault {} v;
-    } ":";
-  };
-
-# the INI file can now be given as plain old nix values
-in customToINI {
-  main = {
-    pushinfo = true;
-    autopush = false;
-    host = "localhost";
-    port = 42;
-  };
-  mergetool = {
-    merge = "diff3";
-  };
-}
-</programlisting>
-
-  <para>
-   This will produce the following INI file as nix string:
-  </para>
-
-<programlisting>
-[main]
-autopush:"no"
-host:"localhost"
-port:42
-pushinfo:"yes"
-str\:ange:"very::strange"
-
-[mergetool]
-merge:"diff3"
-</programlisting>
-
-  <note>
-   <para>
-    Nix store paths can be converted to strings by enclosing a derivation
-    attribute like so: <code>"${drv}"</code>.
-   </para>
-  </note>
-
-  <para>
-   Detailed documentation for each generator can be found in
-   <literal>lib/generators.nix</literal>.
-  </para>
- </section>
- <section xml:id="sec-debug">
-  <title>Debugging Nix Expressions</title>
-
-  <para>
-   Nix is a unityped, dynamic language, this means every value can potentially
-   appear anywhere. Since it is also non-strict, evaluation order and what
-   ultimately is evaluated might surprise you. Therefore it is important to be
-   able to debug nix expressions.
-  </para>
-
-  <para>
-   In the <literal>lib/debug.nix</literal> file you will find a number of
-   functions that help (pretty-)printing values while evaluation is runnnig.
-   You can even specify how deep these values should be printed recursively,
-   and transform them on the fly. Please consult the docstrings in
-   <literal>lib/debug.nix</literal> for usage information.
-  </para>
- </section>
- <section xml:id="sec-fhs-environments">
-  <title>buildFHSUserEnv</title>
-
-  <para>
-   <function>buildFHSUserEnv</function> provides a way to build and run
-   FHS-compatible lightweight sandboxes. It creates an isolated root with bound
-   <filename>/nix/store</filename>, so its footprint in terms of disk space
-   needed is quite small. This allows one to run software which is hard or
-   unfeasible to patch for NixOS -- 3rd-party source trees with FHS
-   assumptions, games distributed as tarballs, software with integrity checking
-   and/or external self-updated binaries. It uses Linux namespaces feature to
-   create temporary lightweight environments which are destroyed after all
-   child processes exit, without root user rights requirement. Accepted
-   arguments are:
-  </para>
-
-  <variablelist>
-   <varlistentry>
-    <term>
-     <literal>name</literal>
-    </term>
-    <listitem>
-     <para>
-      Environment name.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>targetPkgs</literal>
-    </term>
-    <listitem>
-     <para>
-      Packages to be installed for the main host's architecture (i.e. x86_64 on
-      x86_64 installations). Along with libraries binaries are also installed.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>multiPkgs</literal>
-    </term>
-    <listitem>
-     <para>
-      Packages to be installed for all architectures supported by a host (i.e.
-      i686 and x86_64 on x86_64 installations). Only libraries are installed by
-      default.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>extraBuildCommands</literal>
-    </term>
-    <listitem>
-     <para>
-      Additional commands to be executed for finalizing the directory
-      structure.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>extraBuildCommandsMulti</literal>
-    </term>
-    <listitem>
-     <para>
-      Like <literal>extraBuildCommands</literal>, but executed only on multilib
-      architectures.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>extraOutputsToInstall</literal>
-    </term>
-    <listitem>
-     <para>
-      Additional derivation outputs to be linked for both target and
-      multi-architecture packages.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>extraInstallCommands</literal>
-    </term>
-    <listitem>
-     <para>
-      Additional commands to be executed for finalizing the derivation with
-      runner script.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
-     <literal>runScript</literal>
-    </term>
-    <listitem>
-     <para>
-      A command that would be executed inside the sandbox and passed all the
-      command line arguments. It defaults to <literal>bash</literal>.
-     </para>
-    </listitem>
-   </varlistentry>
-  </variablelist>
-
-  <para>
-   One can create a simple environment using a <literal>shell.nix</literal>
-   like that:
-  </para>
-
-<programlisting><![CDATA[
-{ pkgs ? import <nixpkgs> {} }:
-
-(pkgs.buildFHSUserEnv {
-  name = "simple-x11-env";
-  targetPkgs = pkgs: (with pkgs;
-    [ udev
-      alsaLib
-    ]) ++ (with pkgs.xorg;
-    [ libX11
-      libXcursor
-      libXrandr
-    ]);
-  multiPkgs = pkgs: (with pkgs;
-    [ udev
-      alsaLib
-    ]);
-  runScript = "bash";
-}).env
-]]></programlisting>
-
-  <para>
-   Running <literal>nix-shell</literal> would then drop you into a shell with
-   these libraries and binaries available. You can use this to run
-   closed-source applications which expect FHS structure without hassles:
-   simply change <literal>runScript</literal> to the application path, e.g.
-   <filename>./bin/start.sh</filename> -- relative paths are supported.
-  </para>
- </section>
- <xi:include href="shell.section.xml" />
- <section xml:id="sec-pkgs-dockerTools">
-  <title>pkgs.dockerTools</title>
-
-  <para>
-   <varname>pkgs.dockerTools</varname> is a set of functions for creating and
-   manipulating Docker images according to the
-   <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#docker-image-specification-v120">
-   Docker Image Specification v1.2.0 </link>. Docker itself is not used to
-   perform any of the operations done by these functions.
-  </para>
-
-  <warning>
-   <para>
-    The <varname>dockerTools</varname> API is unstable and may be subject to
-    backwards-incompatible changes in the future.
-   </para>
-  </warning>
-
-  <section xml:id="ssec-pkgs-dockerTools-buildImage">
-   <title>buildImage</title>
-
-   <para>
-    This function is analogous to the <command>docker build</command> command,
-    in that can used to build a Docker-compatible repository tarball containing
-    a single image with one or multiple layers. As such, the result is suitable
-    for being loaded in Docker with <command>docker load</command>.
-   </para>
-
-   <para>
-    The parameters of <varname>buildImage</varname> with relative example
-    values are described below:
-   </para>
-
-   <example xml:id='ex-dockerTools-buildImage'>
-    <title>Docker build</title>
-<programlisting>
-buildImage {
-  name = "redis"; <co xml:id='ex-dockerTools-buildImage-1' />
-  tag = "latest"; <co xml:id='ex-dockerTools-buildImage-2' />
-
-  fromImage = someBaseImage; <co xml:id='ex-dockerTools-buildImage-3' />
-  fromImageName = null; <co xml:id='ex-dockerTools-buildImage-4' />
-  fromImageTag = "latest"; <co xml:id='ex-dockerTools-buildImage-5' />
-
-  contents = pkgs.redis; <co xml:id='ex-dockerTools-buildImage-6' />
-  runAsRoot = '' <co xml:id='ex-dockerTools-buildImage-runAsRoot' />
-    #!${stdenv.shell}
-    mkdir -p /data
-  '';
-
-  config = { <co xml:id='ex-dockerTools-buildImage-8' />
-    Cmd = [ "/bin/redis-server" ];
-    WorkingDir = "/data";
-    Volumes = {
-      "/data" = {};
-    };
-  };
-}
-</programlisting>
-   </example>
-
-   <para>
-    The above example will build a Docker image <literal>redis/latest</literal>
-    from the given base image. Loading and running this image in Docker results
-    in <literal>redis-server</literal> being started automatically.
-   </para>
-
-   <calloutlist>
-    <callout arearefs='ex-dockerTools-buildImage-1'>
-     <para>
-      <varname>name</varname> specifies the name of the resulting image. This
-      is the only required argument for <varname>buildImage</varname>.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-2'>
-     <para>
-      <varname>tag</varname> specifies the tag of the resulting image. By
-      default it's <literal>null</literal>, which indicates that the nix output
-      hash will be used as tag.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-3'>
-     <para>
-      <varname>fromImage</varname> is the repository tarball containing the
-      base image. It must be a valid Docker image, such as exported by
-      <command>docker save</command>. By default it's <literal>null</literal>,
-      which can be seen as equivalent to <literal>FROM scratch</literal> of a
-      <filename>Dockerfile</filename>.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-4'>
-     <para>
-      <varname>fromImageName</varname> can be used to further specify the base
-      image within the repository, in case it contains multiple images. By
-      default it's <literal>null</literal>, in which case
-      <varname>buildImage</varname> will peek the first image available in the
-      repository.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-5'>
-     <para>
-      <varname>fromImageTag</varname> can be used to further specify the tag of
-      the base image within the repository, in case an image contains multiple
-      tags. By default it's <literal>null</literal>, in which case
-      <varname>buildImage</varname> will peek the first tag available for the
-      base image.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-6'>
-     <para>
-      <varname>contents</varname> is a derivation that will be copied in the
-      new layer of the resulting image. This can be similarly seen as
-      <command>ADD contents/ /</command> in a <filename>Dockerfile</filename>.
-      By default it's <literal>null</literal>.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-runAsRoot'>
-     <para>
-      <varname>runAsRoot</varname> is a bash script that will run as root in an
-      environment that overlays the existing layers of the base image with the
-      new resulting layer, including the previously copied
-      <varname>contents</varname> derivation. This can be similarly seen as
-      <command>RUN ...</command> in a <filename>Dockerfile</filename>.
-      <note>
-       <para>
-        Using this parameter requires the <literal>kvm</literal> device to be
-        available.
-       </para>
-      </note>
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-buildImage-8'>
-     <para>
-      <varname>config</varname> is used to specify the configuration of the
-      containers that will be started off the built image in Docker. The
-      available options are listed in the
-      <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions">
-      Docker Image Specification v1.2.0 </link>.
-     </para>
-    </callout>
-   </calloutlist>
-
-   <para>
-    After the new layer has been created, its closure (to which
-    <varname>contents</varname>, <varname>config</varname> and
-    <varname>runAsRoot</varname> contribute) will be copied in the layer
-    itself. Only new dependencies that are not already in the existing layers
-    will be copied.
-   </para>
-
-   <para>
-    At the end of the process, only one new single layer will be produced and
-    added to the resulting image.
-   </para>
-
-   <para>
-    The resulting repository will only list the single image
-    <varname>image/tag</varname>. In the case of
-    <xref linkend='ex-dockerTools-buildImage'/> it would be
-    <varname>redis/latest</varname>.
-   </para>
-
-   <para>
-    It is possible to inspect the arguments with which an image was built using
-    its <varname>buildArgs</varname> attribute.
-   </para>
-
-   <note>
-    <para>
-     If you see errors similar to <literal>getProtocolByName: does not exist
-     (no such protocol name: tcp)</literal> you may need to add
-     <literal>pkgs.iana-etc</literal> to <varname>contents</varname>.
-    </para>
-   </note>
-
-   <note>
-    <para>
-     If you see errors similar to <literal>Error_Protocol ("certificate has
-     unknown CA",True,UnknownCa)</literal> you may need to add
-     <literal>pkgs.cacert</literal> to <varname>contents</varname>.
-    </para>
-   </note>
-
-   <example xml:id="example-pkgs-dockerTools-buildImage-creation-date">
-     <title>Impurely Defining a Docker Layer's Creation Date</title>
-     <para>
-       By default <function>buildImage</function> will use a static
-       date of one second past the UNIX Epoch. This allows
-       <function>buildImage</function> to produce binary reproducible
-       images. When listing images with <command>docker list
-       images</command>, the newly created images will be listed like
-       this:
-     </para>
-     <screen><![CDATA[
-$ docker image list
-REPOSITORY   TAG      IMAGE ID       CREATED        SIZE
-hello        latest   08c791c7846e   48 years ago   25.2MB
-]]></screen>
-     <para>
-       You can break binary reproducibility but have a sorted,
-       meaningful <literal>CREATED</literal> column by setting
-       <literal>created</literal> to <literal>now</literal>.
-     </para>
-     <programlisting><![CDATA[
-pkgs.dockerTools.buildImage {
-  name = "hello";
-  tag = "latest";
-  created = "now";
-  contents = pkgs.hello;
-
-  config.Cmd = [ "/bin/hello" ];
-}
-]]></programlisting>
-     <para>
-       and now the Docker CLI will display a reasonable date and
-       sort the images as expected:
-       <screen><![CDATA[
-$ docker image list
-REPOSITORY   TAG      IMAGE ID       CREATED              SIZE
-hello        latest   de2bf4786de6   About a minute ago   25.2MB
-]]></screen>
-       however, the produced images will not be binary reproducible.
-     </para>
-   </example>
-  </section>
-
-  <section xml:id="ssec-pkgs-dockerTools-buildLayeredImage">
-   <title>buildLayeredImage</title>
-
-   <para>
-    Create a Docker image with many of the store paths being on their own layer
-    to improve sharing between images.
-   </para>
-
-   <variablelist>
-    <varlistentry>
-     <term>
-      <varname>name</varname>
-     </term>
-     <listitem>
-      <para>
-       The name of the resulting image.
-      </para>
-     </listitem>
-    </varlistentry>
-    <varlistentry>
-     <term>
-      <varname>tag</varname> <emphasis>optional</emphasis>
-     </term>
-     <listitem>
-      <para>
-       Tag of the generated image.
-      </para>
-      <para>
-       <emphasis>Default:</emphasis> the output path's hash
-      </para>
-     </listitem>
-    </varlistentry>
-    <varlistentry>
-     <term>
-      <varname>contents</varname> <emphasis>optional</emphasis>
-     </term>
-     <listitem>
-      <para>
-       Top level paths in the container. Either a single derivation, or a list
-       of derivations.
-      </para>
-      <para>
-       <emphasis>Default:</emphasis> <literal>[]</literal>
-      </para>
-     </listitem>
-    </varlistentry>
-    <varlistentry>
-     <term>
-      <varname>config</varname> <emphasis>optional</emphasis>
-     </term>
-     <listitem>
-      <para>
-       Run-time configuration of the container. A full list of the options are
-       available at in the
-       <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions">
-       Docker Image Specification v1.2.0 </link>.
-      </para>
-      <para>
-       <emphasis>Default:</emphasis> <literal>{}</literal>
-      </para>
-     </listitem>
-    </varlistentry>
-    <varlistentry>
-     <term>
-      <varname>created</varname> <emphasis>optional</emphasis>
-     </term>
-     <listitem>
-      <para>
-       Date and time the layers were created. Follows the same
-       <literal>now</literal> exception supported by
-       <literal>buildImage</literal>.
-      </para>
-      <para>
-       <emphasis>Default:</emphasis> <literal>1970-01-01T00:00:01Z</literal>
-      </para>
-     </listitem>
-    </varlistentry>
-    <varlistentry>
-     <term>
-      <varname>maxLayers</varname> <emphasis>optional</emphasis>
-     </term>
-     <listitem>
-      <para>
-       Maximum number of layers to create.
-      </para>
-      <para>
-       <emphasis>Default:</emphasis> <literal>24</literal>
-      </para>
-     </listitem>
-    </varlistentry>
-   </variablelist>
-
-   <section xml:id="dockerTools-buildLayeredImage-arg-contents">
-    <title>Behavior of <varname>contents</varname> in the final image</title>
-
-    <para>
-     Each path directly listed in <varname>contents</varname> will have a
-     symlink in the root of the image.
-    </para>
-
-    <para>
-     For example:
-<programlisting><![CDATA[
-pkgs.dockerTools.buildLayeredImage {
-  name = "hello";
-  contents = [ pkgs.hello ];
-}
-]]></programlisting>
-     will create symlinks for all the paths in the <literal>hello</literal>
-     package:
-<screen><![CDATA[
-/bin/hello -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/bin/hello
-/share/info/hello.info -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/info/hello.info
-/share/locale/bg/LC_MESSAGES/hello.mo -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/locale/bg/LC_MESSAGES/hello.mo
-]]></screen>
-    </para>
-   </section>
-
-   <section xml:id="dockerTools-buildLayeredImage-arg-config">
-    <title>Automatic inclusion of <varname>config</varname> references</title>
-
-    <para>
-     The closure of <varname>config</varname> is automatically included in the
-     closure of the final image.
-    </para>
-
-    <para>
-     This allows you to make very simple Docker images with very little code.
-     This container will start up and run <command>hello</command>:
-<programlisting><![CDATA[
-pkgs.dockerTools.buildLayeredImage {
-  name = "hello";
-  config.Cmd = [ "${pkgs.hello}/bin/hello" ];
-}
-]]></programlisting>
-    </para>
-   </section>
-
-   <section xml:id="dockerTools-buildLayeredImage-arg-maxLayers">
-    <title>Adjusting <varname>maxLayers</varname></title>
-
-    <para>
-     Increasing the <varname>maxLayers</varname> increases the number of layers
-     which have a chance to be shared between different images.
-    </para>
-
-    <para>
-     Modern Docker installations support up to 128 layers, however older
-     versions support as few as 42.
-    </para>
-
-    <para>
-     If the produced image will not be extended by other Docker builds, it is
-     safe to set <varname>maxLayers</varname> to <literal>128</literal>.
-     However it will be impossible to extend the image further.
-    </para>
-
-    <para>
-     The first (<literal>maxLayers-2</literal>) most "popular" paths will have
-     their own individual layers, then layer #<literal>maxLayers-1</literal>
-     will contain all the remaining "unpopular" paths, and finally layer
-     #<literal>maxLayers</literal> will contain the Image configuration.
-    </para>
-
-    <para>
-     Docker's Layers are not inherently ordered, they are content-addressable
-     and are not explicitly layered until they are composed in to an Image.
-    </para>
-   </section>
-  </section>
-
-  <section xml:id="ssec-pkgs-dockerTools-fetchFromRegistry">
-   <title>pullImage</title>
-
-   <para>
-    This function is analogous to the <command>docker pull</command> command,
-    in that can be used to pull a Docker image from a Docker registry. By
-    default <link xlink:href="https://hub.docker.com/">Docker Hub</link> is
-    used to pull images.
-   </para>
-
-   <para>
-    Its parameters are described in the example below:
-   </para>
-
-   <example xml:id='ex-dockerTools-pullImage'>
-    <title>Docker pull</title>
-<programlisting>
-pullImage {
-  imageName = "nixos/nix"; <co xml:id='ex-dockerTools-pullImage-1' />
-  imageDigest = "sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b"; <co xml:id='ex-dockerTools-pullImage-2' />
-  finalImageTag = "1.11";  <co xml:id='ex-dockerTools-pullImage-3' />
-  sha256 = "0mqjy3zq2v6rrhizgb9nvhczl87lcfphq9601wcprdika2jz7qh8"; <co xml:id='ex-dockerTools-pullImage-4' />
-  os = "linux"; <co xml:id='ex-dockerTools-pullImage-5' />
-  arch = "x86_64"; <co xml:id='ex-dockerTools-pullImage-6' />
-}
-</programlisting>
-   </example>
-
-   <calloutlist>
-    <callout arearefs='ex-dockerTools-pullImage-1'>
-     <para>
-      <varname>imageName</varname> specifies the name of the image to be
-      downloaded, which can also include the registry namespace (e.g.
-      <literal>nixos</literal>). This argument is required.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-pullImage-2'>
-     <para>
-      <varname>imageDigest</varname> specifies the digest of the image to be
-      downloaded. Skopeo can be used to get the digest of an image, with its
-      <varname>inspect</varname> subcommand. Since a given
-      <varname>imageName</varname> may transparently refer to a manifest list
-      of images which support multiple architectures and/or operating systems,
-      supply the `--override-os` and `--override-arch` arguments to specify
-      exactly which image you want. By default it will match the OS and
-      architecture of the host the command is run on.
-<programlisting>
-$ nix-shell --packages skopeo jq --command "skopeo --override-os linux --override-arch x86_64 inspect docker://docker.io/nixos/nix:1.11 | jq -r '.Digest'"
-sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b
-</programlisting>
-      This argument is required.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-pullImage-3'>
-     <para>
-      <varname>finalImageTag</varname>, if specified, this is the tag of the
-      image to be created. Note it is never used to fetch the image since we
-      prefer to rely on the immutable digest ID. By default it's
-      <literal>latest</literal>.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-pullImage-4'>
-     <para>
-      <varname>sha256</varname> is the checksum of the whole fetched image.
-      This argument is required.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-pullImage-5'>
-     <para>
-      <varname>os</varname>, if specified, is the operating system of the
-      fetched image. By default it's <literal>linux</literal>.
-     </para>
-    </callout>
-    <callout arearefs='ex-dockerTools-pullImage-6'>
-     <para>
-      <varname>arch</varname>, if specified, is the cpu architecture of the
-      fetched image. By default it's <literal>x86_64</literal>.
-     </para>
-    </callout>
-   </calloutlist>
-  </section>
-
-  <section xml:id="ssec-pkgs-dockerTools-exportImage">
-   <title>exportImage</title>
-
-   <para>
-    This function is analogous to the <command>docker export</command> command,
-    in that can used to flatten a Docker image that contains multiple layers.
-    It is in fact the result of the merge of all the layers of the image. As
-    such, the result is suitable for being imported in Docker with
-    <command>docker import</command>.
-   </para>
-
-   <note>
-    <para>
-     Using this function requires the <literal>kvm</literal> device to be
-     available.
-    </para>
-   </note>
-
-   <para>
-    The parameters of <varname>exportImage</varname> are the following:
-   </para>
-
-   <example xml:id='ex-dockerTools-exportImage'>
-    <title>Docker export</title>
-<programlisting>
-exportImage {
-  fromImage = someLayeredImage;
-  fromImageName = null;
-  fromImageTag = null;
-
-  name = someLayeredImage.name;
-}
-  </programlisting>
-   </example>
-
-   <para>
-    The parameters relative to the base image have the same synopsis as
-    described in <xref linkend='ssec-pkgs-dockerTools-buildImage'/>, except
-    that <varname>fromImage</varname> is the only required argument in this
-    case.
-   </para>
-
-   <para>
-    The <varname>name</varname> argument is the name of the derivation output,
-    which defaults to <varname>fromImage.name</varname>.
-   </para>
-  </section>
-
-  <section xml:id="ssec-pkgs-dockerTools-shadowSetup">
-   <title>shadowSetup</title>
-
-   <para>
-    This constant string is a helper for setting up the base files for managing
-    users and groups, only if such files don't exist already. It is suitable
-    for being used in a <varname>runAsRoot</varname>
-    <xref linkend='ex-dockerTools-buildImage-runAsRoot'/> script for cases like
-    in the example below:
-   </para>
-
-   <example xml:id='ex-dockerTools-shadowSetup'>
-    <title>Shadow base files</title>
-<programlisting>
-buildImage {
-  name = "shadow-basic";
-
-  runAsRoot = ''
-    #!${stdenv.shell}
-    ${shadowSetup}
-    groupadd -r redis
-    useradd -r -g redis redis
-    mkdir /data
-    chown redis:redis /data
-  '';
-}
-</programlisting>
-   </example>
-
-   <para>
-    Creating base files like <literal>/etc/passwd</literal> or
-    <literal>/etc/login.defs</literal> are necessary for shadow-utils to
-    manipulate users and groups.
-   </para>
-  </section>
- </section>
+ <xi:include href="functions/overrides.xml" />
+ <xi:include href="functions/generators.xml" />
+ <xi:include href="functions/debug.xml" />
+ <xi:include href="functions/fhs-environments.xml" />
+ <xi:include href="functions/shell.xml" />
+ <xi:include href="functions/dockertools.xml" />
 </chapter>
diff --git a/doc/functions/debug.xml b/doc/functions/debug.xml
new file mode 100644
index 000000000000..c6b3611eea53
--- /dev/null
+++ b/doc/functions/debug.xml
@@ -0,0 +1,21 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-debug">
+ <title>Debugging Nix Expressions</title>
+
+ <para>
+  Nix is a unityped, dynamic language, this means every value can potentially
+  appear anywhere. Since it is also non-strict, evaluation order and what
+  ultimately is evaluated might surprise you. Therefore it is important to be
+  able to debug nix expressions.
+ </para>
+
+ <para>
+  In the <literal>lib/debug.nix</literal> file you will find a number of
+  functions that help (pretty-)printing values while evaluation is runnnig. You
+  can even specify how deep these values should be printed recursively, and
+  transform them on the fly. Please consult the docstrings in
+  <literal>lib/debug.nix</literal> for usage information.
+ </para>
+</section>
diff --git a/doc/functions/dockertools.xml b/doc/functions/dockertools.xml
new file mode 100644
index 000000000000..501f46a967c3
--- /dev/null
+++ b/doc/functions/dockertools.xml
@@ -0,0 +1,564 @@
+<section 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-pkgs-dockerTools">
+ <title>pkgs.dockerTools</title>
+
+ <para>
+  <varname>pkgs.dockerTools</varname> is a set of functions for creating and
+  manipulating Docker images according to the
+  <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#docker-image-specification-v120">
+  Docker Image Specification v1.2.0 </link>. Docker itself is not used to
+  perform any of the operations done by these functions.
+ </para>
+
+ <warning>
+  <para>
+   The <varname>dockerTools</varname> API is unstable and may be subject to
+   backwards-incompatible changes in the future.
+  </para>
+ </warning>
+
+ <section xml:id="ssec-pkgs-dockerTools-buildImage">
+  <title>buildImage</title>
+
+  <para>
+   This function is analogous to the <command>docker build</command> command,
+   in that can used to build a Docker-compatible repository tarball containing
+   a single image with one or multiple layers. As such, the result is suitable
+   for being loaded in Docker with <command>docker load</command>.
+  </para>
+
+  <para>
+   The parameters of <varname>buildImage</varname> with relative example values
+   are described below:
+  </para>
+
+  <example xml:id='ex-dockerTools-buildImage'>
+   <title>Docker build</title>
+<programlisting>
+buildImage {
+  name = "redis"; <co xml:id='ex-dockerTools-buildImage-1' />
+  tag = "latest"; <co xml:id='ex-dockerTools-buildImage-2' />
+
+  fromImage = someBaseImage; <co xml:id='ex-dockerTools-buildImage-3' />
+  fromImageName = null; <co xml:id='ex-dockerTools-buildImage-4' />
+  fromImageTag = "latest"; <co xml:id='ex-dockerTools-buildImage-5' />
+
+  contents = pkgs.redis; <co xml:id='ex-dockerTools-buildImage-6' />
+  runAsRoot = '' <co xml:id='ex-dockerTools-buildImage-runAsRoot' />
+    #!${stdenv.shell}
+    mkdir -p /data
+  '';
+
+  config = { <co xml:id='ex-dockerTools-buildImage-8' />
+    Cmd = [ "/bin/redis-server" ];
+    WorkingDir = "/data";
+    Volumes = {
+      "/data" = {};
+    };
+  };
+}
+</programlisting>
+  </example>
+
+  <para>
+   The above example will build a Docker image <literal>redis/latest</literal>
+   from the given base image. Loading and running this image in Docker results
+   in <literal>redis-server</literal> being started automatically.
+  </para>
+
+  <calloutlist>
+   <callout arearefs='ex-dockerTools-buildImage-1'>
+    <para>
+     <varname>name</varname> specifies the name of the resulting image. This is
+     the only required argument for <varname>buildImage</varname>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-2'>
+    <para>
+     <varname>tag</varname> specifies the tag of the resulting image. By
+     default it's <literal>null</literal>, which indicates that the nix output
+     hash will be used as tag.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-3'>
+    <para>
+     <varname>fromImage</varname> is the repository tarball containing the base
+     image. It must be a valid Docker image, such as exported by
+     <command>docker save</command>. By default it's <literal>null</literal>,
+     which can be seen as equivalent to <literal>FROM scratch</literal> of a
+     <filename>Dockerfile</filename>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-4'>
+    <para>
+     <varname>fromImageName</varname> can be used to further specify the base
+     image within the repository, in case it contains multiple images. By
+     default it's <literal>null</literal>, in which case
+     <varname>buildImage</varname> will peek the first image available in the
+     repository.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-5'>
+    <para>
+     <varname>fromImageTag</varname> can be used to further specify the tag of
+     the base image within the repository, in case an image contains multiple
+     tags. By default it's <literal>null</literal>, in which case
+     <varname>buildImage</varname> will peek the first tag available for the
+     base image.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-6'>
+    <para>
+     <varname>contents</varname> is a derivation that will be copied in the new
+     layer of the resulting image. This can be similarly seen as <command>ADD
+     contents/ /</command> in a <filename>Dockerfile</filename>. By default
+     it's <literal>null</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-runAsRoot'>
+    <para>
+     <varname>runAsRoot</varname> is a bash script that will run as root in an
+     environment that overlays the existing layers of the base image with the
+     new resulting layer, including the previously copied
+     <varname>contents</varname> derivation. This can be similarly seen as
+     <command>RUN ...</command> in a <filename>Dockerfile</filename>.
+     <note>
+      <para>
+       Using this parameter requires the <literal>kvm</literal> device to be
+       available.
+      </para>
+     </note>
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-buildImage-8'>
+    <para>
+     <varname>config</varname> is used to specify the configuration of the
+     containers that will be started off the built image in Docker. The
+     available options are listed in the
+     <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions">
+     Docker Image Specification v1.2.0 </link>.
+    </para>
+   </callout>
+  </calloutlist>
+
+  <para>
+   After the new layer has been created, its closure (to which
+   <varname>contents</varname>, <varname>config</varname> and
+   <varname>runAsRoot</varname> contribute) will be copied in the layer itself.
+   Only new dependencies that are not already in the existing layers will be
+   copied.
+  </para>
+
+  <para>
+   At the end of the process, only one new single layer will be produced and
+   added to the resulting image.
+  </para>
+
+  <para>
+   The resulting repository will only list the single image
+   <varname>image/tag</varname>. In the case of
+   <xref linkend='ex-dockerTools-buildImage'/> it would be
+   <varname>redis/latest</varname>.
+  </para>
+
+  <para>
+   It is possible to inspect the arguments with which an image was built using
+   its <varname>buildArgs</varname> attribute.
+  </para>
+
+  <note>
+   <para>
+    If you see errors similar to <literal>getProtocolByName: does not exist (no
+    such protocol name: tcp)</literal> you may need to add
+    <literal>pkgs.iana-etc</literal> to <varname>contents</varname>.
+   </para>
+  </note>
+
+  <note>
+   <para>
+    If you see errors similar to <literal>Error_Protocol ("certificate has
+    unknown CA",True,UnknownCa)</literal> you may need to add
+    <literal>pkgs.cacert</literal> to <varname>contents</varname>.
+   </para>
+  </note>
+
+  <example xml:id="example-pkgs-dockerTools-buildImage-creation-date">
+   <title>Impurely Defining a Docker Layer's Creation Date</title>
+   <para>
+    By default <function>buildImage</function> will use a static date of one
+    second past the UNIX Epoch. This allows <function>buildImage</function> to
+    produce binary reproducible images. When listing images with
+    <command>docker list images</command>, the newly created images will be
+    listed like this:
+   </para>
+<screen><![CDATA[
+$ docker image list
+REPOSITORY   TAG      IMAGE ID       CREATED        SIZE
+hello        latest   08c791c7846e   48 years ago   25.2MB
+]]></screen>
+   <para>
+    You can break binary reproducibility but have a sorted, meaningful
+    <literal>CREATED</literal> column by setting <literal>created</literal> to
+    <literal>now</literal>.
+   </para>
+<programlisting><![CDATA[
+pkgs.dockerTools.buildImage {
+  name = "hello";
+  tag = "latest";
+  created = "now";
+  contents = pkgs.hello;
+
+  config.Cmd = [ "/bin/hello" ];
+}
+]]></programlisting>
+   <para>
+    and now the Docker CLI will display a reasonable date and sort the images
+    as expected:
+<screen><![CDATA[
+$ docker image list
+REPOSITORY   TAG      IMAGE ID       CREATED              SIZE
+hello        latest   de2bf4786de6   About a minute ago   25.2MB
+]]></screen>
+    however, the produced images will not be binary reproducible.
+   </para>
+  </example>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-buildLayeredImage">
+  <title>buildLayeredImage</title>
+
+  <para>
+   Create a Docker image with many of the store paths being on their own layer
+   to improve sharing between images.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>name</varname>
+    </term>
+    <listitem>
+     <para>
+      The name of the resulting image.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>tag</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Tag of the generated image.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> the output path's hash
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>contents</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Top level paths in the container. Either a single derivation, or a list
+      of derivations.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>[]</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>config</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Run-time configuration of the container. A full list of the options are
+      available at in the
+      <link xlink:href="https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions">
+      Docker Image Specification v1.2.0 </link>.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>{}</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>created</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Date and time the layers were created. Follows the same
+      <literal>now</literal> exception supported by
+      <literal>buildImage</literal>.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>1970-01-01T00:00:01Z</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>maxLayers</varname> <emphasis>optional</emphasis>
+    </term>
+    <listitem>
+     <para>
+      Maximum number of layers to create.
+     </para>
+     <para>
+      <emphasis>Default:</emphasis> <literal>24</literal>
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-contents">
+   <title>Behavior of <varname>contents</varname> in the final image</title>
+
+   <para>
+    Each path directly listed in <varname>contents</varname> will have a
+    symlink in the root of the image.
+   </para>
+
+   <para>
+    For example:
+<programlisting><![CDATA[
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  contents = [ pkgs.hello ];
+}
+]]></programlisting>
+    will create symlinks for all the paths in the <literal>hello</literal>
+    package:
+<screen><![CDATA[
+/bin/hello -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/bin/hello
+/share/info/hello.info -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/info/hello.info
+/share/locale/bg/LC_MESSAGES/hello.mo -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/locale/bg/LC_MESSAGES/hello.mo
+]]></screen>
+   </para>
+  </section>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-config">
+   <title>Automatic inclusion of <varname>config</varname> references</title>
+
+   <para>
+    The closure of <varname>config</varname> is automatically included in the
+    closure of the final image.
+   </para>
+
+   <para>
+    This allows you to make very simple Docker images with very little code.
+    This container will start up and run <command>hello</command>:
+<programlisting><![CDATA[
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  config.Cmd = [ "${pkgs.hello}/bin/hello" ];
+}
+]]></programlisting>
+   </para>
+  </section>
+
+  <section xml:id="dockerTools-buildLayeredImage-arg-maxLayers">
+   <title>Adjusting <varname>maxLayers</varname></title>
+
+   <para>
+    Increasing the <varname>maxLayers</varname> increases the number of layers
+    which have a chance to be shared between different images.
+   </para>
+
+   <para>
+    Modern Docker installations support up to 128 layers, however older
+    versions support as few as 42.
+   </para>
+
+   <para>
+    If the produced image will not be extended by other Docker builds, it is
+    safe to set <varname>maxLayers</varname> to <literal>128</literal>. However
+    it will be impossible to extend the image further.
+   </para>
+
+   <para>
+    The first (<literal>maxLayers-2</literal>) most "popular" paths will have
+    their own individual layers, then layer #<literal>maxLayers-1</literal>
+    will contain all the remaining "unpopular" paths, and finally layer
+    #<literal>maxLayers</literal> will contain the Image configuration.
+   </para>
+
+   <para>
+    Docker's Layers are not inherently ordered, they are content-addressable
+    and are not explicitly layered until they are composed in to an Image.
+   </para>
+  </section>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-fetchFromRegistry">
+  <title>pullImage</title>
+
+  <para>
+   This function is analogous to the <command>docker pull</command> command, in
+   that can be used to pull a Docker image from a Docker registry. By default
+   <link xlink:href="https://hub.docker.com/">Docker Hub</link> is used to pull
+   images.
+  </para>
+
+  <para>
+   Its parameters are described in the example below:
+  </para>
+
+  <example xml:id='ex-dockerTools-pullImage'>
+   <title>Docker pull</title>
+<programlisting>
+pullImage {
+  imageName = "nixos/nix"; <co xml:id='ex-dockerTools-pullImage-1' />
+  imageDigest = "sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b"; <co xml:id='ex-dockerTools-pullImage-2' />
+  finalImageTag = "1.11";  <co xml:id='ex-dockerTools-pullImage-3' />
+  sha256 = "0mqjy3zq2v6rrhizgb9nvhczl87lcfphq9601wcprdika2jz7qh8"; <co xml:id='ex-dockerTools-pullImage-4' />
+  os = "linux"; <co xml:id='ex-dockerTools-pullImage-5' />
+  arch = "x86_64"; <co xml:id='ex-dockerTools-pullImage-6' />
+}
+</programlisting>
+  </example>
+
+  <calloutlist>
+   <callout arearefs='ex-dockerTools-pullImage-1'>
+    <para>
+     <varname>imageName</varname> specifies the name of the image to be
+     downloaded, which can also include the registry namespace (e.g.
+     <literal>nixos</literal>). This argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-2'>
+    <para>
+     <varname>imageDigest</varname> specifies the digest of the image to be
+     downloaded. Skopeo can be used to get the digest of an image, with its
+     <varname>inspect</varname> subcommand. Since a given
+     <varname>imageName</varname> may transparently refer to a manifest list of
+     images which support multiple architectures and/or operating systems,
+     supply the `--override-os` and `--override-arch` arguments to specify
+     exactly which image you want. By default it will match the OS and
+     architecture of the host the command is run on.
+<programlisting>
+$ nix-shell --packages skopeo jq --command "skopeo --override-os linux --override-arch x86_64 inspect docker://docker.io/nixos/nix:1.11 | jq -r '.Digest'"
+sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b
+</programlisting>
+     This argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-3'>
+    <para>
+     <varname>finalImageTag</varname>, if specified, this is the tag of the
+     image to be created. Note it is never used to fetch the image since we
+     prefer to rely on the immutable digest ID. By default it's
+     <literal>latest</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-4'>
+    <para>
+     <varname>sha256</varname> is the checksum of the whole fetched image. This
+     argument is required.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-5'>
+    <para>
+     <varname>os</varname>, if specified, is the operating system of the
+     fetched image. By default it's <literal>linux</literal>.
+    </para>
+   </callout>
+   <callout arearefs='ex-dockerTools-pullImage-6'>
+    <para>
+     <varname>arch</varname>, if specified, is the cpu architecture of the
+     fetched image. By default it's <literal>x86_64</literal>.
+    </para>
+   </callout>
+  </calloutlist>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-exportImage">
+  <title>exportImage</title>
+
+  <para>
+   This function is analogous to the <command>docker export</command> command,
+   in that can used to flatten a Docker image that contains multiple layers. It
+   is in fact the result of the merge of all the layers of the image. As such,
+   the result is suitable for being imported in Docker with <command>docker
+   import</command>.
+  </para>
+
+  <note>
+   <para>
+    Using this function requires the <literal>kvm</literal> device to be
+    available.
+   </para>
+  </note>
+
+  <para>
+   The parameters of <varname>exportImage</varname> are the following:
+  </para>
+
+  <example xml:id='ex-dockerTools-exportImage'>
+   <title>Docker export</title>
+<programlisting>
+exportImage {
+  fromImage = someLayeredImage;
+  fromImageName = null;
+  fromImageTag = null;
+
+  name = someLayeredImage.name;
+}
+  </programlisting>
+  </example>
+
+  <para>
+   The parameters relative to the base image have the same synopsis as
+   described in <xref linkend='ssec-pkgs-dockerTools-buildImage'/>, except that
+   <varname>fromImage</varname> is the only required argument in this case.
+  </para>
+
+  <para>
+   The <varname>name</varname> argument is the name of the derivation output,
+   which defaults to <varname>fromImage.name</varname>.
+  </para>
+ </section>
+
+ <section xml:id="ssec-pkgs-dockerTools-shadowSetup">
+  <title>shadowSetup</title>
+
+  <para>
+   This constant string is a helper for setting up the base files for managing
+   users and groups, only if such files don't exist already. It is suitable for
+   being used in a <varname>runAsRoot</varname>
+   <xref linkend='ex-dockerTools-buildImage-runAsRoot'/> script for cases like
+   in the example below:
+  </para>
+
+  <example xml:id='ex-dockerTools-shadowSetup'>
+   <title>Shadow base files</title>
+<programlisting>
+buildImage {
+  name = "shadow-basic";
+
+  runAsRoot = ''
+    #!${stdenv.shell}
+    ${shadowSetup}
+    groupadd -r redis
+    useradd -r -g redis redis
+    mkdir /data
+    chown redis:redis /data
+  '';
+}
+</programlisting>
+  </example>
+
+  <para>
+   Creating base files like <literal>/etc/passwd</literal> or
+   <literal>/etc/login.defs</literal> are necessary for shadow-utils to
+   manipulate users and groups.
+  </para>
+ </section>
+</section>
diff --git a/doc/functions/fhs-environments.xml b/doc/functions/fhs-environments.xml
new file mode 100644
index 000000000000..79682080be31
--- /dev/null
+++ b/doc/functions/fhs-environments.xml
@@ -0,0 +1,142 @@
+<section 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-fhs-environments">
+ <title>buildFHSUserEnv</title>
+
+ <para>
+  <function>buildFHSUserEnv</function> provides a way to build and run
+  FHS-compatible lightweight sandboxes. It creates an isolated root with bound
+  <filename>/nix/store</filename>, so its footprint in terms of disk space
+  needed is quite small. This allows one to run software which is hard or
+  unfeasible to patch for NixOS -- 3rd-party source trees with FHS assumptions,
+  games distributed as tarballs, software with integrity checking and/or
+  external self-updated binaries. It uses Linux namespaces feature to create
+  temporary lightweight environments which are destroyed after all child
+  processes exit, without root user rights requirement. Accepted arguments are:
+ </para>
+
+ <variablelist>
+  <varlistentry>
+   <term>
+    <literal>name</literal>
+   </term>
+   <listitem>
+    <para>
+     Environment name.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>targetPkgs</literal>
+   </term>
+   <listitem>
+    <para>
+     Packages to be installed for the main host's architecture (i.e. x86_64 on
+     x86_64 installations). Along with libraries binaries are also installed.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>multiPkgs</literal>
+   </term>
+   <listitem>
+    <para>
+     Packages to be installed for all architectures supported by a host (i.e.
+     i686 and x86_64 on x86_64 installations). Only libraries are installed by
+     default.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraBuildCommands</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional commands to be executed for finalizing the directory structure.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraBuildCommandsMulti</literal>
+   </term>
+   <listitem>
+    <para>
+     Like <literal>extraBuildCommands</literal>, but executed only on multilib
+     architectures.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraOutputsToInstall</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional derivation outputs to be linked for both target and
+     multi-architecture packages.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>extraInstallCommands</literal>
+   </term>
+   <listitem>
+    <para>
+     Additional commands to be executed for finalizing the derivation with
+     runner script.
+    </para>
+   </listitem>
+  </varlistentry>
+  <varlistentry>
+   <term>
+    <literal>runScript</literal>
+   </term>
+   <listitem>
+    <para>
+     A command that would be executed inside the sandbox and passed all the
+     command line arguments. It defaults to <literal>bash</literal>.
+    </para>
+   </listitem>
+  </varlistentry>
+ </variablelist>
+
+ <para>
+  One can create a simple environment using a <literal>shell.nix</literal> like
+  that:
+ </para>
+
+<programlisting><![CDATA[
+{ pkgs ? import <nixpkgs> {} }:
+
+(pkgs.buildFHSUserEnv {
+  name = "simple-x11-env";
+  targetPkgs = pkgs: (with pkgs;
+    [ udev
+      alsaLib
+    ]) ++ (with pkgs.xorg;
+    [ libX11
+      libXcursor
+      libXrandr
+    ]);
+  multiPkgs = pkgs: (with pkgs;
+    [ udev
+      alsaLib
+    ]);
+  runScript = "bash";
+}).env
+]]></programlisting>
+
+ <para>
+  Running <literal>nix-shell</literal> would then drop you into a shell with
+  these libraries and binaries available. You can use this to run closed-source
+  applications which expect FHS structure without hassles: simply change
+  <literal>runScript</literal> to the application path, e.g.
+  <filename>./bin/start.sh</filename> -- relative paths are supported.
+ </para>
+</section>
diff --git a/doc/functions/generators.xml b/doc/functions/generators.xml
new file mode 100644
index 000000000000..e860b10e8979
--- /dev/null
+++ b/doc/functions/generators.xml
@@ -0,0 +1,89 @@
+<section 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-generators">
+ <title>Generators</title>
+
+ <para>
+  Generators are functions that create file formats from nix data structures,
+  e. g. for configuration files. There are generators available for:
+  <literal>INI</literal>, <literal>JSON</literal> and <literal>YAML</literal>
+ </para>
+
+ <para>
+  All generators follow a similar call interface: <code>generatorName
+  configFunctions data</code>, where <literal>configFunctions</literal> is an
+  attrset of user-defined functions that format nested parts of the content.
+  They each have common defaults, so often they do not need to be set manually.
+  An example is <code>mkSectionName ? (name: libStr.escape [ "[" "]" ]
+  name)</code> from the <literal>INI</literal> generator. It receives the name
+  of a section and sanitizes it. The default <literal>mkSectionName</literal>
+  escapes <literal>[</literal> and <literal>]</literal> with a backslash.
+ </para>
+
+ <para>
+  Generators can be fine-tuned to produce exactly the file format required by
+  your application/service. One example is an INI-file format which uses
+  <literal>: </literal> as separator, the strings
+  <literal>"yes"</literal>/<literal>"no"</literal> as boolean values and
+  requires all string values to be quoted:
+ </para>
+
+<programlisting>
+with lib;
+let
+  customToINI = generators.toINI {
+    # specifies how to format a key/value pair
+    mkKeyValue = generators.mkKeyValueDefault {
+      # specifies the generated string for a subset of nix values
+      mkValueString = v:
+             if v == true then ''"yes"''
+        else if v == false then ''"no"''
+        else if isString v then ''"${v}"''
+        # and delegats all other values to the default generator
+        else generators.mkValueStringDefault {} v;
+    } ":";
+  };
+
+# the INI file can now be given as plain old nix values
+in customToINI {
+  main = {
+    pushinfo = true;
+    autopush = false;
+    host = "localhost";
+    port = 42;
+  };
+  mergetool = {
+    merge = "diff3";
+  };
+}
+</programlisting>
+
+ <para>
+  This will produce the following INI file as nix string:
+ </para>
+
+<programlisting>
+[main]
+autopush:"no"
+host:"localhost"
+port:42
+pushinfo:"yes"
+str\:ange:"very::strange"
+
+[mergetool]
+merge:"diff3"
+</programlisting>
+
+ <note>
+  <para>
+   Nix store paths can be converted to strings by enclosing a derivation
+   attribute like so: <code>"${drv}"</code>.
+  </para>
+ </note>
+
+ <para>
+  Detailed documentation for each generator can be found in
+  <literal>lib/generators.nix</literal>.
+ </para>
+</section>
diff --git a/doc/functions/overrides.xml b/doc/functions/overrides.xml
new file mode 100644
index 000000000000..99e2a63631a7
--- /dev/null
+++ b/doc/functions/overrides.xml
@@ -0,0 +1,203 @@
+<section 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-overrides">
+ <title>Overriding</title>
+
+ <para>
+  Sometimes one wants to override parts of <literal>nixpkgs</literal>, e.g.
+  derivation attributes, the results of derivations or even the whole package
+  set.
+ </para>
+
+ <section xml:id="sec-pkg-override">
+  <title>&lt;pkg&gt;.override</title>
+
+  <para>
+   The function <varname>override</varname> is usually available for all the
+   derivations in the nixpkgs expression (<varname>pkgs</varname>).
+  </para>
+
+  <para>
+   It is used to override the arguments passed to a function.
+  </para>
+
+  <para>
+   Example usages:
+<programlisting>pkgs.foo.override { arg1 = val1; arg2 = val2; ... }</programlisting>
+<programlisting>
+import pkgs.path { overlays = [ (self: super: {
+  foo = super.foo.override { barSupport = true ; };
+  })]};
+</programlisting>
+<programlisting>
+mypkg = pkgs.callPackage ./mypkg.nix {
+  mydep = pkgs.mydep.override { ... };
+  }
+</programlisting>
+  </para>
+
+  <para>
+   In the first example, <varname>pkgs.foo</varname> is the result of a
+   function call with some default arguments, usually a derivation. Using
+   <varname>pkgs.foo.override</varname> will call the same function with the
+   given new arguments.
+  </para>
+ </section>
+
+ <section xml:id="sec-pkg-overrideAttrs">
+  <title>&lt;pkg&gt;.overrideAttrs</title>
+
+  <para>
+   The function <varname>overrideAttrs</varname> allows overriding the
+   attribute set passed to a <varname>stdenv.mkDerivation</varname> call,
+   producing a new derivation based on the original one. This function is
+   available on all derivations produced by the
+   <varname>stdenv.mkDerivation</varname> function, which is most packages in
+   the nixpkgs expression <varname>pkgs</varname>.
+  </para>
+
+  <para>
+   Example usage:
+<programlisting>
+helloWithDebug = pkgs.hello.overrideAttrs (oldAttrs: rec {
+  separateDebugInfo = true;
+});
+</programlisting>
+  </para>
+
+  <para>
+   In the above example, the <varname>separateDebugInfo</varname> attribute is
+   overridden to be true, thus building debug info for
+   <varname>helloWithDebug</varname>, while all other attributes will be
+   retained from the original <varname>hello</varname> package.
+  </para>
+
+  <para>
+   The argument <varname>oldAttrs</varname> is conventionally used to refer to
+   the attr set originally passed to <varname>stdenv.mkDerivation</varname>.
+  </para>
+
+  <note>
+   <para>
+    Note that <varname>separateDebugInfo</varname> is processed only by the
+    <varname>stdenv.mkDerivation</varname> function, not the generated, raw Nix
+    derivation. Thus, using <varname>overrideDerivation</varname> will not work
+    in this case, as it overrides only the attributes of the final derivation.
+    It is for this reason that <varname>overrideAttrs</varname> should be
+    preferred in (almost) all cases to <varname>overrideDerivation</varname>,
+    i.e. to allow using <varname>sdenv.mkDerivation</varname> to process input
+    arguments, as well as the fact that it is easier to use (you can use the
+    same attribute names you see in your Nix code, instead of the ones
+    generated (e.g. <varname>buildInputs</varname> vs
+    <varname>nativeBuildInputs</varname>, and involves less typing.
+   </para>
+  </note>
+ </section>
+
+ <section xml:id="sec-pkg-overrideDerivation">
+  <title>&lt;pkg&gt;.overrideDerivation</title>
+
+  <warning>
+   <para>
+    You should prefer <varname>overrideAttrs</varname> in almost all cases, see
+    its documentation for the reasons why.
+    <varname>overrideDerivation</varname> is not deprecated and will continue
+    to work, but is less nice to use and does not have as many abilities as
+    <varname>overrideAttrs</varname>.
+   </para>
+  </warning>
+
+  <warning>
+   <para>
+    Do not use this function in Nixpkgs as it evaluates a Derivation before
+    modifying it, which breaks package abstraction and removes error-checking
+    of function arguments. In addition, this evaluation-per-function
+    application incurs a performance penalty, which can become a problem if
+    many overrides are used. It is only intended for ad-hoc customisation, such
+    as in <filename>~/.config/nixpkgs/config.nix</filename>.
+   </para>
+  </warning>
+
+  <para>
+   The function <varname>overrideDerivation</varname> creates a new derivation
+   based on an existing one by overriding the original's attributes with the
+   attribute set produced by the specified function. This function is available
+   on all derivations defined using the <varname>makeOverridable</varname>
+   function. Most standard derivation-producing functions, such as
+   <varname>stdenv.mkDerivation</varname>, are defined using this function,
+   which means most packages in the nixpkgs expression,
+   <varname>pkgs</varname>, have this function.
+  </para>
+
+  <para>
+   Example usage:
+<programlisting>
+mySed = pkgs.gnused.overrideDerivation (oldAttrs: {
+  name = "sed-4.2.2-pre";
+  src = fetchurl {
+    url = ftp://alpha.gnu.org/gnu/sed/sed-4.2.2-pre.tar.bz2;
+    sha256 = "11nq06d131y4wmf3drm0yk502d2xc6n5qy82cg88rb9nqd2lj41k";
+  };
+  patches = [];
+});
+</programlisting>
+  </para>
+
+  <para>
+   In the above example, the <varname>name</varname>, <varname>src</varname>,
+   and <varname>patches</varname> of the derivation will be overridden, while
+   all other attributes will be retained from the original derivation.
+  </para>
+
+  <para>
+   The argument <varname>oldAttrs</varname> is used to refer to the attribute
+   set of the original derivation.
+  </para>
+
+  <note>
+   <para>
+    A package's attributes are evaluated *before* being modified by the
+    <varname>overrideDerivation</varname> function. For example, the
+    <varname>name</varname> attribute reference in <varname>url =
+    "mirror://gnu/hello/${name}.tar.gz";</varname> is filled-in *before* the
+    <varname>overrideDerivation</varname> function modifies the attribute set.
+    This means that overriding the <varname>name</varname> attribute, in this
+    example, *will not* change the value of the <varname>url</varname>
+    attribute. Instead, we need to override both the <varname>name</varname>
+    *and* <varname>url</varname> attributes.
+   </para>
+  </note>
+ </section>
+
+ <section xml:id="sec-lib-makeOverridable">
+  <title>lib.makeOverridable</title>
+
+  <para>
+   The function <varname>lib.makeOverridable</varname> is used to make the
+   result of a function easily customizable. This utility only makes sense for
+   functions that accept an argument set and return an attribute set.
+  </para>
+
+  <para>
+   Example usage:
+<programlisting>
+f = { a, b }: { result = a+b; };
+c = lib.makeOverridable f { a = 1; b = 2; };
+</programlisting>
+  </para>
+
+  <para>
+   The variable <varname>c</varname> is the value of the <varname>f</varname>
+   function applied with some default arguments. Hence the value of
+   <varname>c.result</varname> is <literal>3</literal>, in this example.
+  </para>
+
+  <para>
+   The variable <varname>c</varname> however also has some additional
+   functions, like <link linkend="sec-pkg-override">c.override</link> which can
+   be used to override the default arguments. In this example the value of
+   <varname>(c.override { a = 4; }).result</varname> is 6.
+  </para>
+ </section>
+</section>
diff --git a/doc/functions/shell.xml b/doc/functions/shell.xml
new file mode 100644
index 000000000000..e5031c9463c0
--- /dev/null
+++ b/doc/functions/shell.xml
@@ -0,0 +1,26 @@
+<section 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-pkgs-mkShell">
+ <title>pkgs.mkShell</title>
+
+ <para>
+  <function>pkgs.mkShell</function> is a special kind of derivation that is
+  only useful when using it combined with <command>nix-shell</command>. It will
+  in fact fail to instantiate when invoked with <command>nix-build</command>.
+ </para>
+
+ <section xml:id="sec-pkgs-mkShell-usage">
+  <title>Usage</title>
+
+<programlisting><![CDATA[
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.mkShell {
+  # this will make all the build inputs from hello and gnutar
+  # available to the shell environment
+  inputsFrom = with pkgs; [ hello gnutar ];
+  buildInputs = [ pkgs.gnumake ];
+}
+]]></programlisting>
+ </section>
+</section>
diff --git a/doc/package-notes.xml b/doc/package-notes.xml
index a4322a0234d3..0543e06a05d4 100644
--- a/doc/package-notes.xml
+++ b/doc/package-notes.xml
@@ -668,8 +668,9 @@ overrides = self: super: rec {
     plugins = with availablePlugins; [ python perl ];
   }
 }</programlisting>
-    If the <literal>configure</literal> function returns an attrset without the <literal>plugins</literal>
-    attribute, <literal>availablePlugins</literal> will be used automatically.
+   If the <literal>configure</literal> function returns an attrset without the
+   <literal>plugins</literal> attribute, <literal>availablePlugins</literal>
+   will be used automatically.
   </para>
 
   <para>
@@ -703,9 +704,11 @@ overrides = self: super: rec {
 }; }
 </programlisting>
   </para>
+
   <para>
-    WeeChat allows to set defaults on startup using the <literal>--run-command</literal>.
-    The <literal>configure</literal> method can be used to pass commands to the program:
+   WeeChat allows to set defaults on startup using the
+   <literal>--run-command</literal>. The <literal>configure</literal> method
+   can be used to pass commands to the program:
 <programlisting>weechat.override {
   configure = { availablePlugins, ... }: {
     init = ''
@@ -714,12 +717,14 @@ overrides = self: super: rec {
     '';
   };
 }</programlisting>
-    Further values can be added to the list of commands when running
-    <literal>weechat --run-command "your-commands"</literal>.
+   Further values can be added to the list of commands when running
+   <literal>weechat --run-command "your-commands"</literal>.
   </para>
+
   <para>
-    Additionally it's possible to specify scripts to be loaded when starting <literal>weechat</literal>.
-    These will be loaded before the commands from <literal>init</literal>:
+   Additionally it's possible to specify scripts to be loaded when starting
+   <literal>weechat</literal>. These will be loaded before the commands from
+   <literal>init</literal>:
 <programlisting>weechat.override {
   configure = { availablePlugins, ... }: {
     scripts = with pkgs.weechatScripts; [
@@ -731,11 +736,13 @@ overrides = self: super: rec {
   };
 }</programlisting>
   </para>
+
   <para>
-    In <literal>nixpkgs</literal> there's a subpackage which contains derivations for
-    WeeChat scripts. Such derivations expect a <literal>passthru.scripts</literal> attribute
-    which contains a list of all scripts inside the store path. Furthermore all scripts
-    have to live in <literal>$out/share</literal>. An exemplary derivation looks like this:
+   In <literal>nixpkgs</literal> there's a subpackage which contains
+   derivations for WeeChat scripts. Such derivations expect a
+   <literal>passthru.scripts</literal> attribute which contains a list of all
+   scripts inside the store path. Furthermore all scripts have to live in
+   <literal>$out/share</literal>. An exemplary derivation looks like this:
 <programlisting>{ stdenv, fetchurl }:
 
 stdenv.mkDerivation {
@@ -814,20 +821,26 @@ citrix_receiver.override {
  <section xml:id="sec-ibus-typing-booster">
   <title>ibus-engines.typing-booster</title>
 
-  <para>This package is an ibus-based completion method to speed up typing.</para>
+  <para>
+   This package is an ibus-based completion method to speed up typing.
+  </para>
 
   <section xml:id="sec-ibus-typing-booster-activate">
    <title>Activating the engine</title>
 
    <para>
-    IBus needs to be configured accordingly to activate <literal>typing-booster</literal>. The configuration
-    depends on the desktop manager in use. For detailed instructions, please refer to the
-    <link xlink:href="https://mike-fabian.github.io/ibus-typing-booster/documentation.html">upstream docs</link>.
+    IBus needs to be configured accordingly to activate
+    <literal>typing-booster</literal>. The configuration depends on the desktop
+    manager in use. For detailed instructions, please refer to the
+    <link xlink:href="https://mike-fabian.github.io/ibus-typing-booster/documentation.html">upstream
+    docs</link>.
    </para>
+
    <para>
-    On NixOS you need to explicitly enable <literal>ibus</literal> with given engines
-    before customizing your desktop to use <literal>typing-booster</literal>. This can be achieved
-    using the <literal>ibus</literal> module:
+    On NixOS you need to explicitly enable <literal>ibus</literal> with given
+    engines before customizing your desktop to use
+    <literal>typing-booster</literal>. This can be achieved using the
+    <literal>ibus</literal> module:
 <programlisting>{ pkgs, ... }: {
   i18n.inputMethod = {
     enabled = "ibus";
@@ -841,17 +854,20 @@ citrix_receiver.override {
    <title>Using custom hunspell dictionaries</title>
 
    <para>
-    The IBus engine is based on <literal>hunspell</literal> to support completion in many languages.
-    By default the dictionaries <literal>de-de</literal>, <literal>en-us</literal>, <literal>es-es</literal>,
-    <literal>it-it</literal>, <literal>sv-se</literal> and <literal>sv-fi</literal>
-    are in use. To add another dictionary, the package can be overridden like this:
+    The IBus engine is based on <literal>hunspell</literal> to support
+    completion in many languages. By default the dictionaries
+    <literal>de-de</literal>, <literal>en-us</literal>,
+    <literal>es-es</literal>, <literal>it-it</literal>,
+    <literal>sv-se</literal> and <literal>sv-fi</literal> are in use. To add
+    another dictionary, the package can be overridden like this:
 <programlisting>ibus-engines.typing-booster.override {
   langs = [ "de-at" "en-gb" ];
 }</programlisting>
    </para>
+
    <para>
-     <emphasis>Note: each language passed to <literal>langs</literal> must be an attribute name in
-     <literal>pkgs.hunspellDicts</literal>.</emphasis>
+    <emphasis>Note: each language passed to <literal>langs</literal> must be an
+    attribute name in <literal>pkgs.hunspellDicts</literal>.</emphasis>
    </para>
   </section>
 
@@ -859,10 +875,12 @@ citrix_receiver.override {
    <title>Built-in emoji picker</title>
 
    <para>
-    The <literal>ibus-engines.typing-booster</literal> package contains a program
-    named <literal>emoji-picker</literal>. To display all emojis correctly,
-    a special font such as <literal>noto-fonts-emoji</literal> is needed:
+    The <literal>ibus-engines.typing-booster</literal> package contains a
+    program named <literal>emoji-picker</literal>. To display all emojis
+    correctly, a special font such as <literal>noto-fonts-emoji</literal> is
+    needed:
    </para>
+
    <para>
     On NixOS it can be installed using the following expression:
 <programlisting>{ pkgs, ... }: {
diff --git a/doc/shell.section.md b/doc/shell.section.md
deleted file mode 100644
index cb8832a814fc..000000000000
--- a/doc/shell.section.md
+++ /dev/null
@@ -1,22 +0,0 @@
----
-title: pkgs.mkShell
-author: zimbatm
-date: 2017-10-30
----
-
-# mkShell
-
-pkgs.mkShell is a special kind of derivation that is only useful when using
-it combined with nix-shell. It will in fact fail to instantiate when invoked
-with nix-build.
-
-## Usage
-
-```nix
-{ pkgs ? import <nixpkgs> {} }:
-pkgs.mkShell {
-  # this will make all the build inputs from hello and gnutar available to the shell environment
-  inputsFrom = with pkgs; [ hello gnutar ];
-  buildInputs = [ pkgs.gnumake ];
-}
-```