"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
+ SPDX-License-Identifier: LGPL-2.1+
+
This file is part of systemd.
Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="os-release">
shell style. All strings should be in UTF-8 format, and
non-printable characters should not be used. It is not supported
to concatenate multiple individually quoted strings. Lines
- beginning with "#" shall be ignored as comments.</para>
+ beginning with "#" shall be ignored as comments. Blank lines are
+ permitted and ignored.</para>
<para>The file <filename>/etc/os-release</filename> takes
precedence over <filename>/usr/lib/os-release</filename>.
appropriate.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>VERSION_CODENAME=</varname></term>
+
+ <listitem><para>
+ A lower-case string (no spaces or other characters outside of
+ 0–9, a–z, ".", "_" and "-") identifying the operating system
+ release code name, excluding any OS name information or
+ release version, and suitable for processing by scripts or
+ usage in generated filenames. This field is optional and may
+ not be implemented on all systems.
+ Examples:
+ <literal>VERSION_CODENAME=buster</literal>,
+ <literal>VERSION_CODENAME=xenial</literal>
+ </para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>VERSION_ID=</varname></term>