pyrox.dev
1<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-declarative-package-mgmt">
2 <title>Declarative Package Management</title>
3 <para>
4 With declarative package management, you specify which packages you
5 want on your system by setting the option
6 <xref linkend="opt-environment.systemPackages" />. For instance,
7 adding the following line to <literal>configuration.nix</literal>
8 enables the Mozilla Thunderbird email application:
9 </para>
10 <programlisting language="bash">
11environment.systemPackages = [ pkgs.thunderbird ];
12</programlisting>
13 <para>
14 The effect of this specification is that the Thunderbird package
15 from Nixpkgs will be built or downloaded as part of the system when
16 you run <literal>nixos-rebuild switch</literal>.
17 </para>
18 <note>
19 <para>
20 Some packages require additional global configuration such as
21 D-Bus or systemd service registration so adding them to
22 <xref linkend="opt-environment.systemPackages" /> might not be
23 sufficient. You are advised to check the
24 <link linkend="ch-options">list of options</link> whether a NixOS
25 module for the package does not exist.
26 </para>
27 </note>
28 <para>
29 You can get a list of the available packages as follows:
30 </para>
31 <programlisting>
32$ nix-env -qaP '*' --description
33nixos.firefox firefox-23.0 Mozilla Firefox - the browser, reloaded
34...
35</programlisting>
36 <para>
37 The first column in the output is the <emphasis>attribute
38 name</emphasis>, such as <literal>nixos.thunderbird</literal>.
39 </para>
40 <para>
41 Note: the <literal>nixos</literal> prefix tells us that we want to
42 get the package from the <literal>nixos</literal> channel and works
43 only in CLI tools. In declarative configuration use
44 <literal>pkgs</literal> prefix (variable).
45 </para>
46 <para>
47 To <quote>uninstall</quote> a package, simply remove it from
48 <xref linkend="opt-environment.systemPackages" /> and run
49 <literal>nixos-rebuild switch</literal>.
50 </para>
51 <xi:include href="customizing-packages.section.xml" />
52 <xi:include href="adding-custom-packages.section.xml" />
53</section>