man/os-release.xml - systemd-stable - Rivoreo Source Code Repositories

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 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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   SPDX-License-Identifier: LGPL-2.1+
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 <refentry id="os-release">
   <refentryinfo>
     <title>os-release</title>
     <productname>systemd</productname>
   </refentryinfo>

   <refmeta>
     <refentrytitle>os-release</refentrytitle>
     <manvolnum>5</manvolnum>
   </refmeta>

   <refnamediv>
     <refname>os-release</refname>
     <refpurpose>Operating system identification</refpurpose>
   </refnamediv>

   <refsynopsisdiv>
     <para><filename>/etc/os-release</filename></para>
     <para><filename>/usr/lib/os-release</filename></para>
   </refsynopsisdiv>

   <refsect1>
     <title>Description</title>

     <para>The <filename>/etc/os-release</filename> and
     <filename>/usr/lib/os-release</filename> files contain operating
     system identification data.</para>

     <para>The basic file format of <filename>os-release</filename> is
     a newline-separated list of environment-like shell-compatible
     variable assignments. It is possible to source the configuration
     from shell scripts, however, beyond mere variable assignments, no
     shell features are supported (this means variable expansion is
     explicitly not supported), allowing applications to read the file
     without implementing a shell compatible execution engine. Variable
     assignment values must be enclosed in double or single quotes if
     they include spaces, semicolons or other special characters
     outside of A–Z, a–z, 0–9. Shell special characters ("$", quotes,
     backslash, backtick) must be escaped with backslashes, following
     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. Blank lines are
     permitted and ignored.</para>

     <para>The file <filename>/etc/os-release</filename> takes
     precedence over <filename>/usr/lib/os-release</filename>.
     Applications should check for the former, and exclusively use its
     data if it exists, and only fall back to
     <filename>/usr/lib/os-release</filename> if it is missing.
     Applications should not read data from both files at the same
     time. <filename>/usr/lib/os-release</filename> is the recommended
     place to store OS release information as part of vendor trees.
     <filename>/etc/os-release</filename> should be a relative symlink
     to <filename>/usr/lib/os-release</filename>, to provide
     compatibility with applications only looking at
     <filename>/etc</filename>. A relative symlink instead of an
     absolute symlink is necessary to avoid breaking the link in a
     chroot or initrd environment such as dracut.</para>

     <para><filename>os-release</filename> contains data that is
     defined by the operating system vendor and should generally not be
     changed by the administrator.</para>

     <para>As this file only encodes names and identifiers it should
     not be localized.</para>

     <para>The <filename>/etc/os-release</filename> and
     <filename>/usr/lib/os-release</filename> files might be symlinks
     to other files, but it is important that the file is available
     from earliest boot on, and hence must be located on the root file
     system.</para>

     <para>For a longer rationale for <filename>os-release</filename>
     please refer to the <ulink
     url="http://0pointer.de/blog/projects/os-release">Announcement of <filename>/etc/os-release</filename></ulink>.</para>
   </refsect1>

   <refsect1>
     <title>Options</title>

     <para>The following OS identifications parameters may be set using
     <filename>os-release</filename>:</para>

     <variablelist>

       <varlistentry>
         <term><varname>NAME=</varname></term>

         <listitem><para>A string identifying the operating system,
         without a version component, and suitable for presentation to
         the user. If not set, defaults to
         <literal>NAME=Linux</literal>. Example:
         <literal>NAME=Fedora</literal> or <literal>NAME="Debian
         GNU/Linux"</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>VERSION=</varname></term>

         <listitem><para>A string identifying the operating system
         version, excluding any OS name information, possibly including
         a release code name, and suitable for presentation to the
         user. This field is optional. Example:
         <literal>VERSION=17</literal> or <literal>VERSION="17 (Beefy
         Miracle)"</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>ID=</varname></term>

         <listitem><para>A lower-case string (no spaces or other
         characters outside of 0–9, a–z, ".", "_" and "-") identifying
         the operating system, excluding any version information and
         suitable for processing by scripts or usage in generated
         filenames. If not set, defaults to
         <literal>ID=linux</literal>. Example:
         <literal>ID=fedora</literal> or
         <literal>ID=debian</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>ID_LIKE=</varname></term>

         <listitem><para>A space-separated list of operating system
         identifiers in the same syntax as the <varname>ID=</varname>
         setting. It should list identifiers of operating systems that
         are closely related to the local operating system in regards
         to packaging and programming interfaces, for example listing
         one or more OS identifiers the local OS is a derivative from.
         An OS should generally only list other OS identifiers it
         itself is a derivative of, and not any OSes that are derived
         from it, though symmetric relationships are possible. Build
         scripts and similar should check this variable if they need to
         identify the local operating system and the value of
         <varname>ID=</varname> is not recognized. Operating systems
         should be listed in order of how closely the local operating
         system relates to the listed ones, starting with the closest.
         This field is optional. Example: for an operating system with
         <literal>ID=centos</literal>, an assignment of
         <literal>ID_LIKE="rhel fedora"</literal> would be appropriate.
         For an operating system with <literal>ID=ubuntu</literal>, an
         assignment of <literal>ID_LIKE=debian</literal> is
         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>

         <listitem><para>A lower-case string (mostly numeric, no spaces
         or other characters outside of 0–9, a–z, ".", "_" and "-")
         identifying the operating system version, excluding any OS
         name information or release code name, and suitable for
         processing by scripts or usage in generated filenames. This
         field is optional. Example: <literal>VERSION_ID=17</literal>
         or <literal>VERSION_ID=11.04</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>PRETTY_NAME=</varname></term>

         <listitem><para>A pretty operating system name in a format
         suitable for presentation to the user. May or may not contain
         a release code name or OS version of some kind, as suitable.
         If not set, defaults to
         <literal>PRETTY_NAME="Linux"</literal>. Example:
         <literal>PRETTY_NAME="Fedora 17 (Beefy
         Miracle)"</literal>.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>ANSI_COLOR=</varname></term>

         <listitem><para>A suggested presentation color when showing
         the OS name on the console. This should be specified as string
         suitable for inclusion in the ESC [ m ANSI/ECMA-48 escape code
         for setting graphical rendition. This field is optional.
         Example: <literal>ANSI_COLOR="0;31"</literal> for red, or
         <literal>ANSI_COLOR="1;34"</literal> for light
         blue.</para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>CPE_NAME=</varname></term>

         <listitem><para>A CPE name for the operating system, in URI
         binding syntax, following the
         <ulink url="http://scap.nist.gov/specifications/cpe/">Common
         Platform Enumeration Specification</ulink> as proposed by the
         NIST. This field is optional. Example:
         <literal>CPE_NAME="cpe:/o:fedoraproject:fedora:17"</literal>
         </para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>HOME_URL=</varname></term>
         <term><varname>DOCUMENTATION_URL=</varname></term>
         <term><varname>SUPPORT_URL=</varname></term>
         <term><varname>BUG_REPORT_URL=</varname></term>
         <term><varname>PRIVACY_POLICY_URL=</varname></term>

         <listitem><para>Links to resources on the Internet related to
         the operating system.
         <varname>HOME_URL=</varname> should refer to the homepage of
         the operating system, or alternatively some homepage of the
         specific version of the operating system.
         <varname>DOCUMENTATION_URL=</varname> should refer to the main
         documentation page for this operating system.
         <varname>SUPPORT_URL=</varname> should refer to the main
         support page for the operating system, if there is any. This
         is primarily intended for operating systems which vendors
         provide support for. <varname>BUG_REPORT_URL=</varname> should
         refer to the main bug reporting page for the operating system,
         if there is any. This is primarily intended for operating
         systems that rely on community QA.
         <varname>PRIVACY_POLICY_URL=</varname> should refer to the
         main privacy policy page for the operating system, if there is
         any. These settings are optional, and providing only some of
         these settings is common. These URLs are intended to be
         exposed in "About this system" UIs behind links with captions
         such as "About this Operating System", "Obtain Support",
         "Report a Bug", or "Privacy Policy". The values should be in
         <ulink url="https://tools.ietf.org/html/rfc3986">RFC3986
         format</ulink>, and should be <literal>http:</literal> or
         <literal>https:</literal> URLs, and possibly
         <literal>mailto:</literal> or <literal>tel:</literal>. Only
         one URL shall be listed in each setting. If multiple resources
         need to be referenced, it is recommended to provide an online
         landing page linking all available resources. Examples:
         <literal>HOME_URL="https://fedoraproject.org/"</literal> and
         <literal>BUG_REPORT_URL="https://bugzilla.redhat.com/"</literal></para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>BUILD_ID=</varname></term>

         <listitem><para>A string uniquely identifying the system image
         used as the origin for a distribution (it is not updated with
         system updates). The field can be identical between different
         VERSION_IDs as BUILD_ID is an only a unique identifier to a
         specific version. Distributions that release each update as a
         new version would only need to use VERSION_ID as each build is
         already distinct based on the VERSION_ID. This field is
         optional. Example: <literal>BUILD_ID="2013-03-20.3"</literal>
         or <literal>BUILD_ID=201303203</literal>.

         </para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>VARIANT=</varname></term>

         <listitem><para>
         A string identifying a specific variant or edition of the
         operating system suitable for presentation to the user. This
         field may be used to inform the user that the configuration of
         this system is subject to a specific divergent set of rules or
         default configuration settings. This field is optional and may
         not be implemented on all systems.
         Examples:
         <literal>VARIANT="Server Edition"</literal>,
         <literal>VARIANT="Smart Refrigerator Edition"</literal>
         Note: this field is for display purposes only. The
         <varname>VARIANT_ID</varname> field should be used for making
         programmatic decisions.
         </para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>VARIANT_ID=</varname></term>

         <listitem><para>
         A lower-case string (no spaces or other characters outside of
         0–9, a–z, ".", "_" and "-"), identifying a specific variant or
         edition of the operating system. This may be interpreted by
         other packages in order to determine a divergent default
         configuration. This field is optional and may not be
         implemented on all systems.
         Examples:
         <literal>VARIANT_ID=server</literal>,
         <literal>VARIANT_ID=embedded</literal>
         </para></listitem>
       </varlistentry>

       <varlistentry>
         <term><varname>LOGO=</varname></term>

         <listitem><para>
         A string, specifying the name of an icon as defined by <ulink
         url="http://standards.freedesktop.org/icon-theme-spec/latest">
         freedesktop.org Icon Theme Specification</ulink>. This can be
         used by graphical applications to display an operating
         system's or distributor's logo. This field is optional and
         may not necessarily be implemented on all systems.
         Examples:
         <literal>LOGO=fedora-logo</literal>,
         <literal>LOGO=distributor-logo-opensuse</literal>
         </para></listitem>
       </varlistentry>

     </variablelist>

     <para>If you are reading this file from C code or a shell script
     to determine the OS or a specific version of it, use the
     <varname>ID</varname> and <varname>VERSION_ID</varname> fields,
     possibly with <varname>ID_LIKE</varname> as fallback for
     <varname>ID</varname>. When looking for an OS identification
     string for presentation to the user use the
     <varname>PRETTY_NAME</varname> field.</para>

     <para>Note that operating system vendors may choose not to provide
     version information, for example to accommodate for rolling
     releases. In this case, <varname>VERSION</varname> and
     <varname>VERSION_ID</varname> may be unset. Applications should
     not rely on these fields to be set.</para>

     <para>Operating system vendors may extend the file
     format and introduce new fields. It is highly
     recommended to prefix new fields with an OS specific
     name in order to avoid name clashes. Applications
     reading this file must ignore unknown fields. Example:
     <literal>DEBIAN_BTS="debbugs://bugs.debian.org/"</literal></para>
   </refsect1>

   <refsect1>
     <title>Example</title>

     <programlisting>NAME=Fedora
 VERSION="17 (Beefy Miracle)"
 ID=fedora
 VERSION_ID=17
 PRETTY_NAME="Fedora 17 (Beefy Miracle)"
 ANSI_COLOR="0;34"
 CPE_NAME="cpe:/o:fedoraproject:fedora:17"
 HOME_URL="https://fedoraproject.org/"
 BUG_REPORT_URL="https://bugzilla.redhat.com/"</programlisting>
   </refsect1>

   <refsect1>
       <title>See Also</title>
       <para>
         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
         <citerefentry project='die-net'><refentrytitle>lsb_release</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
         <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>
       </para>
   </refsect1>

 </refentry>
	<?xml version='1.0'?> <!---nxml--->
	<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
	"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

	<!--
	SPDX-License-Identifier: LGPL-2.1+
	-->

	<refentry id="os-release">
	<refentryinfo>
	<title>os-release</title>
	<productname>systemd</productname>
	</refentryinfo>

	<refmeta>
	<refentrytitle>os-release</refentrytitle>
	<manvolnum>5</manvolnum>
	</refmeta>

	<refnamediv>
	<refname>os-release</refname>
	<refpurpose>Operating system identification</refpurpose>
	</refnamediv>

	<refsynopsisdiv>
	<para><filename>/etc/os-release</filename></para>
	<para><filename>/usr/lib/os-release</filename></para>
	</refsynopsisdiv>

	<refsect1>
	<title>Description</title>

	<para>The <filename>/etc/os-release</filename> and
	<filename>/usr/lib/os-release</filename> files contain operating
	system identification data.</para>

	<para>The basic file format of <filename>os-release</filename> is
	a newline-separated list of environment-like shell-compatible
	variable assignments. It is possible to source the configuration
	from shell scripts, however, beyond mere variable assignments, no
	shell features are supported (this means variable expansion is
	explicitly not supported), allowing applications to read the file
	without implementing a shell compatible execution engine. Variable
	assignment values must be enclosed in double or single quotes if
	they include spaces, semicolons or other special characters
	outside of A–Z, a–z, 0–9. Shell special characters ("$", quotes,
	backslash, backtick) must be escaped with backslashes, following
	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. Blank lines are
	permitted and ignored.</para>

	<para>The file <filename>/etc/os-release</filename> takes
	precedence over <filename>/usr/lib/os-release</filename>.
	Applications should check for the former, and exclusively use its
	data if it exists, and only fall back to
	<filename>/usr/lib/os-release</filename> if it is missing.
	Applications should not read data from both files at the same
	time. <filename>/usr/lib/os-release</filename> is the recommended
	place to store OS release information as part of vendor trees.
	<filename>/etc/os-release</filename> should be a relative symlink
	to <filename>/usr/lib/os-release</filename>, to provide
	compatibility with applications only looking at
	<filename>/etc</filename>. A relative symlink instead of an
	absolute symlink is necessary to avoid breaking the link in a
	chroot or initrd environment such as dracut.</para>

	<para><filename>os-release</filename> contains data that is
	defined by the operating system vendor and should generally not be
	changed by the administrator.</para>

	<para>As this file only encodes names and identifiers it should
	not be localized.</para>

	<para>The <filename>/etc/os-release</filename> and
	<filename>/usr/lib/os-release</filename> files might be symlinks
	to other files, but it is important that the file is available
	from earliest boot on, and hence must be located on the root file
	system.</para>

	<para>For a longer rationale for <filename>os-release</filename>
	please refer to the <ulink
	url="http://0pointer.de/blog/projects/os-release">Announcement of <filename>/etc/os-release</filename></ulink>.</para>
	</refsect1>

	<refsect1>
	<title>Options</title>

	<para>The following OS identifications parameters may be set using
	<filename>os-release</filename>:</para>

	<variablelist>

	<varlistentry>
	<term><varname>NAME=</varname></term>

	<listitem><para>A string identifying the operating system,
	without a version component, and suitable for presentation to
	the user. If not set, defaults to
	<literal>NAME=Linux</literal>. Example:
	<literal>NAME=Fedora</literal> or <literal>NAME="Debian
	GNU/Linux"</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>VERSION=</varname></term>

	<listitem><para>A string identifying the operating system
	version, excluding any OS name information, possibly including
	a release code name, and suitable for presentation to the
	user. This field is optional. Example:
	<literal>VERSION=17</literal> or <literal>VERSION="17 (Beefy
	Miracle)"</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>ID=</varname></term>

	<listitem><para>A lower-case string (no spaces or other
	characters outside of 0–9, a–z, ".", "_" and "-") identifying
	the operating system, excluding any version information and
	suitable for processing by scripts or usage in generated
	filenames. If not set, defaults to
	<literal>ID=linux</literal>. Example:
	<literal>ID=fedora</literal> or
	<literal>ID=debian</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>ID_LIKE=</varname></term>

	<listitem><para>A space-separated list of operating system
	identifiers in the same syntax as the <varname>ID=</varname>
	setting. It should list identifiers of operating systems that
	are closely related to the local operating system in regards
	to packaging and programming interfaces, for example listing
	one or more OS identifiers the local OS is a derivative from.
	An OS should generally only list other OS identifiers it
	itself is a derivative of, and not any OSes that are derived
	from it, though symmetric relationships are possible. Build
	scripts and similar should check this variable if they need to
	identify the local operating system and the value of
	<varname>ID=</varname> is not recognized. Operating systems
	should be listed in order of how closely the local operating
	system relates to the listed ones, starting with the closest.
	This field is optional. Example: for an operating system with
	<literal>ID=centos</literal>, an assignment of
	<literal>ID_LIKE="rhel fedora"</literal> would be appropriate.
	For an operating system with <literal>ID=ubuntu</literal>, an
	assignment of <literal>ID_LIKE=debian</literal> is
	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>

	<listitem><para>A lower-case string (mostly numeric, no spaces
	or other characters outside of 0–9, a–z, ".", "_" and "-")
	identifying the operating system version, excluding any OS
	name information or release code name, and suitable for
	processing by scripts or usage in generated filenames. This
	field is optional. Example: <literal>VERSION_ID=17</literal>
	or <literal>VERSION_ID=11.04</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>PRETTY_NAME=</varname></term>

	<listitem><para>A pretty operating system name in a format
	suitable for presentation to the user. May or may not contain
	a release code name or OS version of some kind, as suitable.
	If not set, defaults to
	<literal>PRETTY_NAME="Linux"</literal>. Example:
	<literal>PRETTY_NAME="Fedora 17 (Beefy
	Miracle)"</literal>.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>ANSI_COLOR=</varname></term>

	<listitem><para>A suggested presentation color when showing
	the OS name on the console. This should be specified as string
	suitable for inclusion in the ESC [ m ANSI/ECMA-48 escape code
	for setting graphical rendition. This field is optional.
	Example: <literal>ANSI_COLOR="0;31"</literal> for red, or
	<literal>ANSI_COLOR="1;34"</literal> for light
	blue.</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>CPE_NAME=</varname></term>

	<listitem><para>A CPE name for the operating system, in URI
	binding syntax, following the
	<ulink url="http://scap.nist.gov/specifications/cpe/">Common
	Platform Enumeration Specification</ulink> as proposed by the
	NIST. This field is optional. Example:
	<literal>CPE_NAME="cpe:/o:fedoraproject:fedora:17"</literal>
	</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>HOME_URL=</varname></term>
	<term><varname>DOCUMENTATION_URL=</varname></term>
	<term><varname>SUPPORT_URL=</varname></term>
	<term><varname>BUG_REPORT_URL=</varname></term>
	<term><varname>PRIVACY_POLICY_URL=</varname></term>

	<listitem><para>Links to resources on the Internet related to
	the operating system.
	<varname>HOME_URL=</varname> should refer to the homepage of
	the operating system, or alternatively some homepage of the
	specific version of the operating system.
	<varname>DOCUMENTATION_URL=</varname> should refer to the main
	documentation page for this operating system.
	<varname>SUPPORT_URL=</varname> should refer to the main
	support page for the operating system, if there is any. This
	is primarily intended for operating systems which vendors
	provide support for. <varname>BUG_REPORT_URL=</varname> should
	refer to the main bug reporting page for the operating system,
	if there is any. This is primarily intended for operating
	systems that rely on community QA.
	<varname>PRIVACY_POLICY_URL=</varname> should refer to the
	main privacy policy page for the operating system, if there is
	any. These settings are optional, and providing only some of
	these settings is common. These URLs are intended to be
	exposed in "About this system" UIs behind links with captions
	such as "About this Operating System", "Obtain Support",
	"Report a Bug", or "Privacy Policy". The values should be in
	<ulink url="https://tools.ietf.org/html/rfc3986">RFC3986
	format</ulink>, and should be <literal>http:</literal> or
	<literal>https:</literal> URLs, and possibly
	<literal>mailto:</literal> or <literal>tel:</literal>. Only
	one URL shall be listed in each setting. If multiple resources
	need to be referenced, it is recommended to provide an online
	landing page linking all available resources. Examples:
	<literal>HOME_URL="https://fedoraproject.org/"</literal> and
	<literal>BUG_REPORT_URL="https://bugzilla.redhat.com/"</literal></para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>BUILD_ID=</varname></term>

	<listitem><para>A string uniquely identifying the system image
	used as the origin for a distribution (it is not updated with
	system updates). The field can be identical between different
	VERSION_IDs as BUILD_ID is an only a unique identifier to a
	specific version. Distributions that release each update as a
	new version would only need to use VERSION_ID as each build is
	already distinct based on the VERSION_ID. This field is
	optional. Example: <literal>BUILD_ID="2013-03-20.3"</literal>
	or <literal>BUILD_ID=201303203</literal>.

	</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>VARIANT=</varname></term>

	<listitem><para>
	A string identifying a specific variant or edition of the
	operating system suitable for presentation to the user. This
	field may be used to inform the user that the configuration of
	this system is subject to a specific divergent set of rules or
	default configuration settings. This field is optional and may
	not be implemented on all systems.
	Examples:
	<literal>VARIANT="Server Edition"</literal>,
	<literal>VARIANT="Smart Refrigerator Edition"</literal>
	Note: this field is for display purposes only. The
	<varname>VARIANT_ID</varname> field should be used for making
	programmatic decisions.
	</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>VARIANT_ID=</varname></term>

	<listitem><para>
	A lower-case string (no spaces or other characters outside of
	0–9, a–z, ".", "_" and "-"), identifying a specific variant or
	edition of the operating system. This may be interpreted by
	other packages in order to determine a divergent default
	configuration. This field is optional and may not be
	implemented on all systems.
	Examples:
	<literal>VARIANT_ID=server</literal>,
	<literal>VARIANT_ID=embedded</literal>
	</para></listitem>
	</varlistentry>

	<varlistentry>
	<term><varname>LOGO=</varname></term>

	<listitem><para>
	A string, specifying the name of an icon as defined by <ulink
	url="http://standards.freedesktop.org/icon-theme-spec/latest">
	freedesktop.org Icon Theme Specification</ulink>. This can be
	used by graphical applications to display an operating
	system's or distributor's logo. This field is optional and
	may not necessarily be implemented on all systems.
	Examples:
	<literal>LOGO=fedora-logo</literal>,
	<literal>LOGO=distributor-logo-opensuse</literal>
	</para></listitem>
	</varlistentry>

	</variablelist>

	<para>If you are reading this file from C code or a shell script
	to determine the OS or a specific version of it, use the
	<varname>ID</varname> and <varname>VERSION_ID</varname> fields,
	possibly with <varname>ID_LIKE</varname> as fallback for
	<varname>ID</varname>. When looking for an OS identification
	string for presentation to the user use the
	<varname>PRETTY_NAME</varname> field.</para>

	<para>Note that operating system vendors may choose not to provide
	version information, for example to accommodate for rolling
	releases. In this case, <varname>VERSION</varname> and
	<varname>VERSION_ID</varname> may be unset. Applications should
	not rely on these fields to be set.</para>

	<para>Operating system vendors may extend the file
	format and introduce new fields. It is highly
	recommended to prefix new fields with an OS specific
	name in order to avoid name clashes. Applications
	reading this file must ignore unknown fields. Example:
	<literal>DEBIAN_BTS="debbugs://bugs.debian.org/"</literal></para>
	</refsect1>

	<refsect1>
	<title>Example</title>

	<programlisting>NAME=Fedora
	VERSION="17 (Beefy Miracle)"
	ID=fedora
	VERSION_ID=17
	PRETTY_NAME="Fedora 17 (Beefy Miracle)"
	ANSI_COLOR="0;34"
	CPE_NAME="cpe:/o:fedoraproject:fedora:17"
	HOME_URL="https://fedoraproject.org/"
	BUG_REPORT_URL="https://bugzilla.redhat.com/"</programlisting>
	</refsect1>

	<refsect1>
	<title>See Also</title>
	<para>
	<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	<citerefentry project='die-net'><refentrytitle>lsb_release</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
	<citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>
	</para>
	</refsect1>

	</refentry>