<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> file
- contains operating system identification data.</para>
+ <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
+ 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
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
+ 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><filename>/etc/os-release</filename> contains
- data that is defined by the operating system vendor
- and should not be changed by the administrator.</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 file <filename>/etc/os-release</filename> might
- be a symlink to another file, but it is important that
+ <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>/etc/os-release</filename> please refer to
+ <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>
<title>Options</title>
<para>The following OS identifications parameters may be set using
- <filename>/etc/os-release</filename>:</para>
+ <filename>os-release</filename>:</para>
<variablelist>
<listitem><para>A string identifying
the operating system, without a
version component, and suitable for
- presentation to the user. If not set
+ presentation to the user. If not set,
defaults to
<literal>NAME=Linux</literal>. Example:
<literal>NAME=Fedora</literal> or
excluding any version information and
suitable for processing by scripts or
usage in generated filenames. If not
- set defaults to
+ set, defaults to
<literal>ID=linux</literal>. Example:
<literal>ID=fedora</literal> or
<literal>ID=debian</literal>.</para></listitem>
<listitem><para>A space-separated list
of operating system identifiers in the
same syntax as the
- <varname>ID=</varname> setting. Should
+ <varname>ID=</varname> setting. It should
list identifiers of operating systems
that are closely related to the local
operating system in regards to
OS is a derivative from. An
OS should generally only list other OS
identifiers it itself is a derivative
- from, and not any OSes that
- are derived from it, but symmetric
+ 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
closest. This field is
optional. Example: for an operating
system with
- <literal>ID=centos</literal> an
+ <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
+ with <literal>ID=ubuntu</literal>, an
assignment of
<literal>ID_LIKE=debian</literal> is
appropriate.</para></listitem>
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
+ not set, defaults to
<literal>PRETTY_NAME="Linux"</literal>. Example:
<literal>PRETTY_NAME="Fedora 17 (Beefy
Miracle)"</literal>.</para></listitem>
<literal>tel:</literal>. Only one URL
shall be listed in each setting. If
multiple resources need to be
- referenced it is recommended to
+ referenced, it is recommended to
provide an online landing page linking
all available resources. Examples:
<literal>HOME_URL="https://fedoraproject.org/"</literal>
<para>Note that operating system vendors may choose
not to provide version information, for example to
- accommodate for rolling releases. In this case VERSION
+ 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>
~ianmdlvl / elogind.git / blobdiff