path: root/doc/manual/nix-build.xml

<refentry xmlns="http://docbook.org/ns/docbook"
          xmlns:xlink="http://www.w3.org/1999/xlink">

<refnamediv>
  <refname>nix-build</refname>
  <refpurpose>build a Nix expression</refpurpose>
</refnamediv>

<refsynopsisdiv>
  <cmdsynopsis>
    <command>nix-build</command>
    <arg><option>--add-drv-link</option></arg>
    <arg><option>--no-link</option></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>

<note><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></note>

<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>

<variablelist>

  <varlistentry><term><option>--add-drv-link</option></term>
  
    <listitem><para>Add a symlink in the current directory to the
    store derivation produced by <command>nix-instantiate</command>.
    The symlink is called <filename>derivation</filename> (which is
    numbered in the case of multiple derivations).  The derivation is
    a root of the garbage collector until the symlink is deleted or
    renamed.</para></listitem>
    
  </varlistentry>

  <varlistentry><term><option>--no-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>

</variablelist>

</refsection>


</refentry>