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systemd/man/os-release.xml
2014-10-08 08:30:22 -04:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
<!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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<refentry id="os-release">
<refentryinfo>
<title>os-release</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</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 should be enclosed
in double or single quotes if they include spaces,
semicolons or other special characters outside of A-Z,
a-z, 0-9. All strings should be in UTF-8 format, and
non-printable characters should not be used. If double
or single quotes or backslashes are to be used within
variable assignments, they should be escaped with
backslashes, following shell style. It is not
supported to concatenate multiple individually quoted
strings. Lines beginning with "#" shall be ignored as
comments.</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_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, following the <ulink
url="https://cpe.mitre.org/specification/">Common
Platform Enumeration
Specification</ulink> as proposed by
the MITRE Corporation. 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>SUPPORT_URL=</varname></term>
<term><varname>BUG_REPORT_URL=</varname></term>
<listitem><para>Links to resources on
the Internet related 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>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. 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",
and "Report a Bug". 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>
</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 ID and VERSION_ID fields, possibly with
ID_LIKE as fallback for ID. When looking for an OS
identification string for presentation to the user use
the PRETTY_NAME 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, VERSION
and VERSION_ID 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><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>