nixpkgs/nixos/doc/manual/man-nixos-option.xml
Chuck 59c5bfc86b nixos/nixos-option: Rewrite in a more suitable language
Also add --all, which shows the value of all options.  Diffing the --all
output on either side of contemplated changes is a lovely way to better
understand what's going on inside nixos.
2019-11-04 15:11:44 +01:00

123 lines
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<refentry xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refmeta>
<refentrytitle><command>nixos-option</command>
</refentrytitle><manvolnum>8</manvolnum>
<refmiscinfo class="source">NixOS</refmiscinfo>
<!-- <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> -->
</refmeta>
<refnamediv>
<refname><command>nixos-option</command></refname>
<refpurpose>inspect a NixOS configuration</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>nixos-option</command>
<arg>
<option>-I</option> <replaceable>path</replaceable>
</arg>
<arg>
<option>--all</option>
</arg>
<arg>
<replaceable>option.name</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsection>
<title>Description</title>
<para>
This command evaluates the configuration specified in
<filename>/etc/nixos/configuration.nix</filename> and returns the properties
of the option name given as argument.
</para>
<para>
When the option name is not an option, the command prints the list of
attributes contained in the attribute set.
</para>
</refsection>
<refsection>
<title>Options</title>
<para>
This command accepts the following options:
</para>
<variablelist>
<varlistentry>
<term>
<option>-I</option> <replaceable>path</replaceable>
</term>
<listitem>
<para>
This option is passed to the underlying
<command>nix-instantiate</command> invocation.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>--all</option>
</term>
<listitem>
<para>
Print the values of all options.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Environment</title>
<variablelist>
<varlistentry>
<term>
<envar>NIXOS_CONFIG</envar>
</term>
<listitem>
<para>
Path to the main NixOS configuration module. Defaults to
<filename>/etc/nixos/configuration.nix</filename>.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsection>
<refsection>
<title>Examples</title>
<para>
Investigate option values:
<screen><prompt>$ </prompt>nixos-option boot.loader
This attribute set contains:
generationsDir
grub
initScript
<prompt>$ </prompt>nixos-option boot.loader.grub.enable
Value:
true
Default:
true
Description:
Whether to enable the GNU GRUB boot loader.
Declared by:
"/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/system/boot/loader/grub/grub.nix"
Defined by:
"/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/system/boot/loader/grub/grub.nix"
</screen>
</para>
</refsection>
<refsection>
<title>Bugs</title>
<para>
The author listed in the following section is wrong. If there is any other
bug, please report to Nicolas Pierron.
</para>
</refsection>
</refentry>