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<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-trivial-builders">
 <title>Trivial builders</title>

 <para>
   There are a couple of functions provide in Nixpkgs that help with
   building derivations. The most important one,
   <function>stdenv.mkDerivation</function>, has already been
   documented above. These wrap
   <function>stdenv.mkDerivation</function>, making it easier to use
   in certain cases.
 </para>

 <variablelist>
  <varlistentry>
   <term>
    <literal>runCommand</literal>
   </term>
   <listitem>
     <para>
       This takes three arguments, <literal>name</literal>,
       <literal>env</literal>, and <literal>buildCommand</literal>.
       <literal>name</literal> is just the name that Nix will use to
       refer to the derivation. <literal>env</literal> is an attribute
       set specifying environment variables that will be set for this
       derivation. <literal>buildCommand</literal> specifies the
       commands that will be run to create this derivation. Note that
       you will need to create <literal>$out</literal> for Nix to
       register the command as successful.
    </para>
   </listitem>
  </varlistentry>
  <varlistentry>
   <term>
    <literal>runCommandCC</literal>
   </term>
   <listitem>
     <para>
       This works just like <literal>runCommand</literal>. The only
       difference is that it also provides a C compiler for your use.
       To minimize your dependencies, you should only use this if you
       are sure you will need a C compiler as part of running your command.
    </para>
   </listitem>
  </varlistentry>
  <varlistentry>
   <term>
    <literal>writeTextFile</literal>
   </term>
   <listitem>
     <para>
       This writes <literal>text</literal> to the Nix store. This is
       useful for creating scripts from Nix expressions. This takes an
       attribute set and expects two arguments,
       <literal>name</literal> and <literal>text</literal>.
       <literal>name</literal> corresponds to the name used in the Nix
       store path. <literal>text</literal> will be the contents of the
       file. You can also set <literal>executable</literal> to true to
       make this file have the executable bit set.
    </para>
   </listitem>
  </varlistentry>
  <varlistentry>
   <term>
    <literal>symlinkJoin</literal>
   </term>
   <listitem>
    <para>
     This can be used to put many derivations into the same directory
     structure. It works by creating a new derivation and adding
     symlinks to each of the paths listed. It expects two arguments,
     <literal>name</literal>, and <literal>paths</literal>.
     <literal>name</literal> is the name used in the Nix store path
     for the created derivation. <literal>paths</literal> is a list of
     paths that will be symlinked. These paths can be to Nix store
     derivations or any other directory.
    </para>
   </listitem>
  </varlistentry>
 </variablelist>

</section>