diff options
Diffstat (limited to 'man/os-release.xml')
| -rw-r--r-- | man/os-release.xml | 650 |
1 files changed, 650 insertions, 0 deletions
diff --git a/man/os-release.xml b/man/os-release.xml new file mode 100644 index 0000000..f2e0f3e --- /dev/null +++ b/man/os-release.xml @@ -0,0 +1,650 @@ +<?xml version='1.0'?> <!--*-nxml-*--> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> +<!-- SPDX-License-Identifier: LGPL-2.1-or-later --> + +<refentry id="os-release" xmlns:xi="http://www.w3.org/2001/XInclude"> + <refentryinfo> + <title>os-release</title> + <productname>systemd</productname> + </refentryinfo> + + <refmeta> + <refentrytitle>os-release</refentrytitle> + <manvolnum>5</manvolnum> + </refmeta> + + <refnamediv> + <refname>os-release</refname> + <refname>initrd-release</refname> + <refname>extension-release</refname> + <refpurpose>Operating system identification</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <para><filename>/etc/os-release</filename></para> + <para><filename>/usr/lib/os-release</filename></para> + <para><filename>/etc/initrd-release</filename></para> + <para><filename>/usr/lib/extension-release.d/extension-release.<replaceable>IMAGE</replaceable></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 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 + Bourne 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. (Assignments that do not include these special characters may be enclosed in quotes too, but this is + optional.) Shell special characters ("$", quotes, backslash, backtick) must be escaped with backslashes, + following shell style. All strings should be in UTF-8 encoding, and non-printable characters should not + be used. Concatenation of multiple individually quoted strings is not supported. Lines beginning with "#" + are treated 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><filename>os-release</filename> must not contain repeating keys. Nevertheless, readers should pick + the entries later in the file in case of repeats, similarly to how a shell sourcing the file would. A + reader may warn about repeating entries.</para> + + <para>For a longer rationale for <filename>os-release</filename> + please refer to the <ulink + url="https://0pointer.de/blog/projects/os-release">Announcement of <filename>/etc/os-release</filename></ulink>.</para> + + <refsect2> + <title><filename>/etc/initrd-release</filename></title> + + <para>In the <ulink + url="https://docs.kernel.org/admin-guide/initrd.html">initrd</ulink>, + <filename>/etc/initrd-release</filename> plays the same role as <filename>os-release</filename> in the + main system. Additionally, the presence of that file means that the system is in the initrd phase. + <filename>/etc/os-release</filename> should be symlinked to <filename>/etc/initrd-release</filename> + (or vice versa), so programs that only look for <filename>/etc/os-release</filename> (as described + above) work correctly.</para> + + <para>The rest of this document that talks about <filename>os-release</filename> should be understood + to apply to <filename>initrd-release</filename> too.</para> + </refsect2> + + <refsect2> + <title><filename>/usr/lib/extension-release.d/extension-release.<replaceable>IMAGE</replaceable></filename></title> + + <para><filename>/usr/lib/extension-release.d/extension-release.<replaceable>IMAGE</replaceable></filename> + plays the same role for extension images as <filename>os-release</filename> for the main system, and + follows the syntax and rules as described in the <ulink + url="https://systemd.io/PORTABLE_SERVICES">Portable Services</ulink> page. The purpose of this + file is to identify the extension and to allow the operating system to verify that the extension image + matches the base OS. This is typically implemented by checking that the <varname>ID=</varname> options + match, and either <varname>SYSEXT_LEVEL=</varname> exists and matches too, or if it is not present, + <varname>VERSION_ID=</varname> exists and matches. This ensures ABI/API compatibility between the + layers and prevents merging of an incompatible image in an overlay.</para> + + <para>In order to identify the extension image itself, the same fields defined below can be added to the + <filename>extension-release</filename> file with a <varname>SYSEXT_</varname> prefix (to disambiguate + from fields used to match on the base image). E.g.: <varname>SYSEXT_ID=myext</varname>, + <varname>SYSEXT_VERSION_ID=1.2.3</varname>.</para> + + <para>In the <filename>extension-release.<replaceable>IMAGE</replaceable></filename> filename, the + <replaceable>IMAGE</replaceable> part must exactly match the file name of the containing image with the + suffix removed. In case it is not possible to guarantee that an image file name is stable and doesn't + change between the build and the deployment phases, it is possible to relax this check: if exactly one + file whose name matches <literal><filename>extension-release.*</filename></literal> is present in this + directory, and the file is tagged with a <varname>user.extension-release.strict</varname> + <citerefentry project='man-pages'><refentrytitle>xattr</refentrytitle><manvolnum>7</manvolnum></citerefentry> set to the + string <literal>0</literal>, it will be used instead.</para> + + <para>The rest of this document that talks about <filename>os-release</filename> should be understood + to apply to <filename>extension-release</filename> too.</para> + </refsect2> + </refsect1> + + <refsect1> + <title>Options</title> + + <para>The following OS identifications parameters may be set using + <filename>os-release</filename>:</para> + + <refsect2> + <title>General information identifying the operating system</title> + + <variablelist class='environment-variables'> + <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, a default of <literal>NAME=Linux</literal> may + be used.</para> + + <para>Examples: <literal>NAME=Fedora</literal>, <literal>NAME="Debian GNU/Linux"</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, a default of + <literal>ID=linux</literal> may be used. Note that even though this string may not include + characters that require shell quoting, quoting may nevertheless be used.</para> + + <para>Examples: <literal>ID=fedora</literal>, <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.</para> + + <para>Examples: 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>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, a default of <literal>PRETTY_NAME="Linux"</literal> may be used</para> + + <para>Example: <literal>PRETTY_NAME="Fedora 17 (Beefy Miracle)"</literal>.</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.</para> + + <para>Example: <literal>CPE_NAME="cpe:/o:fedoraproject:fedora:17"</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.</para> + + <para>Examples: <literal>VARIANT="Server Edition"</literal>, <literal>VARIANT="Smart Refrigerator + Edition"</literal>.</para> + + <para>Note: this field is for display purposes only. The <varname>VARIANT_ID</varname> field should + be used for making programmatic decisions.</para> + + <xi:include href="version-info.xml" xpointer="v220"/></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.</para> + + <para>Examples: <literal>VARIANT_ID=server</literal>, <literal>VARIANT_ID=embedded</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v220"/></listitem> + </varlistentry> + </variablelist> + </refsect2> + + <refsect2> + <title>Information about the version of the operating system</title> + + <variablelist class='environment-variables'> + <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.</para> + + <para>Examples: <literal>VERSION=17</literal>, <literal>VERSION="17 (Beefy Miracle)"</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.</para> + + <para>Examples: <literal>VERSION_ID=17</literal>, <literal>VERSION_ID=11.04</literal>. + </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.</para> + + <para>Examples: <literal>VERSION_CODENAME=buster</literal>, + <literal>VERSION_CODENAME=xenial</literal>.</para> + + <xi:include href="version-info.xml" xpointer="v231"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>BUILD_ID=</varname></term> + + <listitem><para>A string uniquely identifying the system image originally used as the installation + base. In most cases, <varname>VERSION_ID</varname> or + <varname>IMAGE_ID</varname>+<varname>IMAGE_VERSION</varname> are updated when the entire system + image is replaced during an update. <varname>BUILD_ID</varname> may be used in distributions where + the original installation image version is important: <varname>VERSION_ID</varname> would change + during incremental system updates, but <varname>BUILD_ID</varname> would not. This field is + optional.</para> + + <para>Examples: <literal>BUILD_ID="2013-03-20.3"</literal>, <literal>BUILD_ID=201303203</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v200"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>IMAGE_ID=</varname></term> + + <listitem><para> A lower-case string (no spaces or other characters outside of 0–9, a–z, ".", "_" + and "-"), identifying a specific image of the operating system. This is supposed to be used for + environments where OS images are prepared, built, shipped and updated as comprehensive, consistent + OS images. This field is optional and may not be implemented on all systems, in particularly not on + those that are not managed via images but put together and updated from individual packages and on + the local system.</para> + + <para>Examples: <literal>IMAGE_ID=vendorx-cashier-system</literal>, + <literal>IMAGE_ID=netbook-image</literal>.</para> + + <xi:include href="version-info.xml" xpointer="v249"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>IMAGE_VERSION=</varname></term> + + <listitem><para>A lower-case string (mostly numeric, no spaces or other characters outside of 0–9, + a–z, ".", "_" and "-") identifying the OS image version. This is supposed to be used together with + <varname>IMAGE_ID</varname> described above, to discern different versions of the same image. + </para> + + <para>Examples: <literal>IMAGE_VERSION=33</literal>, <literal>IMAGE_VERSION=47.1rc1</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v249"/></listitem> + </varlistentry> + </variablelist> + + <para>To summarize: if the image updates are built and shipped as comprehensive units, + <varname>IMAGE_ID</varname>+<varname>IMAGE_VERSION</varname> is the best fit. Otherwise, if updates + eventually completely replace previously installed contents, as in a typical binary distribution, + <varname>VERSION_ID</varname> should be used to identify major releases of the operating system. + <varname>BUILD_ID</varname> may be used instead or in addition to <varname>VERSION_ID</varname> when + the original system image version is important.</para> + </refsect2> + + <refsect2> + <title>Presentation information and links</title> + + <variablelist class='environment-variables'> + <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.</para> + + <para>Examples: <literal>HOME_URL="https://fedoraproject.org/"</literal>, + <literal>BUG_REPORT_URL="https://bugzilla.redhat.com/"</literal>.</para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>SUPPORT_END=</varname></term> + + <listitem><para>The date at which support for this version of the OS ends. (What exactly "lack of + support" means varies between vendors, but generally users should assume that updates, including + security fixes, will not be provided.) The value is a date in the ISO 8601 format + <literal>YYYY-MM-DD</literal>, and specifies the first day on which support <emphasis>is + not</emphasis> provided.</para> + + <para>For example, <literal>SUPPORT_END=2001-01-01</literal> means that the system was supported + until the end of the last day of the previous millennium.</para> + + <xi:include href="version-info.xml" xpointer="v252"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>LOGO=</varname></term> + + <listitem><para>A string, specifying the name of an icon as defined by <ulink + url="https://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.</para> + + <para>Examples: <literal>LOGO=fedora-logo</literal>, <literal>LOGO=distributor-logo-opensuse</literal> + </para> + + <xi:include href="version-info.xml" xpointer="v240"/></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.</para> + + <para>Examples: <literal>ANSI_COLOR="0;31"</literal> for red, <literal>ANSI_COLOR="1;34"</literal> + for light blue, or <literal>ANSI_COLOR="0;38;2;60;110;180"</literal> for Fedora blue. + </para></listitem> + </varlistentry> + + <varlistentry> + <term><varname>VENDOR_NAME=</varname></term> + + <listitem><para>The name of the OS vendor. This is the name of the organization or company which + produces the OS. This field is optional.</para> + + <para>This name is intended to be exposed in "About this system" UIs or software update UIs when + needed to distinguish the OS vendor from the OS itself. It is intended to be human readable.</para> + + <para>Examples: <literal>VENDOR_NAME="Fedora Project"</literal> for Fedora Linux, + <literal>VENDOR_NAME="Canonical"</literal> for Ubuntu.</para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>VENDOR_URL=</varname></term> + + <listitem><para>The homepage of the OS vendor. This field is optional. The + <varname>VENDOR_NAME=</varname> field should be set if this one is, although clients must be + robust against either field not being set.</para> + + <para>The value 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. Only one URL shall be listed in the + setting.</para> + + <para>Examples: <literal>VENDOR_URL="https://fedoraproject.org/"</literal>, + <literal>VENDOR_URL="https://canonical.com/"</literal>.</para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + </variablelist> + </refsect2> + + <refsect2> + <title>Distribution-level defaults and metadata</title> + + <variablelist class='environment-variables'> + <varlistentry> + <term><varname>DEFAULT_HOSTNAME=</varname></term> + + <listitem><para>A string specifying the hostname if + <citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry> is not + present and no other configuration source specifies the hostname. Must be either a single DNS label + (a string composed of 7-bit ASCII lower-case characters and no spaces or dots, limited to the + format allowed for DNS domain name labels), or a sequence of such labels separated by single dots + that forms a valid DNS FQDN. The hostname must be at most 64 characters, which is a Linux + limitation (DNS allows longer names).</para> + + <para>See <citerefentry><refentrytitle>org.freedesktop.hostname1</refentrytitle><manvolnum>5</manvolnum></citerefentry> + for a description of how + <citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry> + determines the fallback hostname.</para> + + <xi:include href="version-info.xml" xpointer="v248"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>ARCHITECTURE=</varname></term> + <listitem><para>A string that specifies which CPU architecture the userspace binaries require. + The architecture identifiers are the same as for <varname>ConditionArchitecture=</varname> + described in <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. + The field is optional and should only be used when just single architecture is supported. + It may provide redundant information when used in a GPT partition with a GUID type that already + encodes the architecture. If this is not the case, the architecture should be specified in + e.g., an extension image, to prevent an incompatible host from loading it. + </para> + + <xi:include href="version-info.xml" xpointer="v252"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>SYSEXT_LEVEL=</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 extensions support level, to indicate which + extension images are supported. See <filename>/usr/lib/extension-release.d/extension-release.<replaceable>IMAGE</replaceable></filename>, + <ulink url="https://docs.kernel.org/admin-guide/initrd.html">initrd</ulink> and + <citerefentry><refentrytitle>systemd-sysext</refentrytitle><manvolnum>8</manvolnum></citerefentry>) + for more information.</para> + + <para>Examples: <literal>SYSEXT_LEVEL=2</literal>, <literal>SYSEXT_LEVEL=15.14</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v248"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>CONFEXT_LEVEL=</varname></term> + + <listitem><para>Semantically the same as <varname>SYSEXT_LEVEL=</varname> but for confext images. + See <filename>/etc/extension-release.d/extension-release.<replaceable>IMAGE</replaceable></filename> + for more information.</para> + + <para>Examples: <literal>CONFEXT_LEVEL=2</literal>, <literal>CONFEXT_LEVEL=15.14</literal>. + </para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>SYSEXT_SCOPE=</varname></term> + <listitem><para>Takes a space-separated list of one or more of the strings + <literal>system</literal>, <literal>initrd</literal> and <literal>portable</literal>. This field is + only supported in <filename>extension-release.d/</filename> files and indicates what environments + the system extension is applicable to: i.e. to regular systems, to initrds, or to portable service + images. If unspecified, <literal>SYSEXT_SCOPE=system portable</literal> is implied, i.e. any system + extension without this field is applicable to regular systems and to portable service environments, + but not to initrd environments.</para> + + <xi:include href="version-info.xml" xpointer="v250"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>CONFEXT_SCOPE=</varname></term> + + <listitem><para>Semantically the same as <varname>SYSEXT_SCOPE=</varname> but for confext images.</para> + + <xi:include href="version-info.xml" xpointer="v254"/></listitem> + </varlistentry> + + <varlistentry> + <term><varname>PORTABLE_PREFIXES=</varname></term> + <listitem><para>Takes a space-separated list of one or more valid prefix match strings for the + <ulink url="https://systemd.io/PORTABLE_SERVICES">Portable Services</ulink> logic. + This field serves two purposes: it is informational, identifying portable service images as such + (and thus allowing them to be distinguished from other OS images, such as bootable system images). + It is also used when a portable service image is attached: the specified or implied portable + service prefix is checked against the list specified here, to enforce restrictions how images may + be attached to a system.</para> + + <xi:include href="version-info.xml" xpointer="v250"/></listitem> + </varlistentry> + </variablelist> + </refsect2> + + <refsect2> + <title>Notes</title> + + <para>If you are using this file 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.</para> + + <para>Example: <literal>DEBIAN_BTS="debbugs://bugs.debian.org/"</literal>.</para> + + <para>Container and sandbox runtime managers may make the host's identification data available to + applications by providing the host's <filename>/etc/os-release</filename> (if available, otherwise + <filename>/usr/lib/os-release</filename> as a fallback) as + <filename>/run/host/os-release</filename>.</para> + </refsect2> + </refsect1> + + <refsect1> + <title>Examples</title> + + <example> + <title><filename>os-release</filename> file for Fedora Workstation</title> + + <programlisting>NAME=Fedora +VERSION="32 (Workstation Edition)" +ID=fedora +VERSION_ID=32 +PRETTY_NAME="Fedora 32 (Workstation Edition)" +ANSI_COLOR="0;38;2;60;110;180" +LOGO=fedora-logo-icon +CPE_NAME="cpe:/o:fedoraproject:fedora:32" +HOME_URL="https://fedoraproject.org/" +DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f32/system-administrators-guide/" +SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help" +BUG_REPORT_URL="https://bugzilla.redhat.com/" +REDHAT_BUGZILLA_PRODUCT="Fedora" +REDHAT_BUGZILLA_PRODUCT_VERSION=32 +REDHAT_SUPPORT_PRODUCT="Fedora" +REDHAT_SUPPORT_PRODUCT_VERSION=32 +PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy" +VARIANT="Workstation Edition" +VARIANT_ID=workstation</programlisting> + </example> + + <example> + <title><filename>extension-release</filename> file for an extension for Fedora Workstation 32</title> + + <programlisting>ID=fedora +VERSION_ID=32</programlisting> + </example> + + <example> + <title>Reading <filename>os-release</filename> in + <citerefentry project='man-pages'><refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum></citerefentry></title> + + <programlisting><xi:include href="check-os-release.sh" parse="text" /></programlisting> + </example> + + <example> + <title>Reading <filename>os-release</filename> in + <citerefentry project='die-net'><refentrytitle>python</refentrytitle><manvolnum>1</manvolnum></citerefentry> (versions >= 3.10)</title> + + <programlisting><xi:include href="check-os-release-simple.py" parse="text" /></programlisting> + + <para>See docs for <ulink url="https://docs.python.org/3/library/platform.html#platform.freedesktop_os_release"> + <function>platform.freedesktop_os_release</function></ulink> for more details. + </para> + </example> + + <example> + <title>Reading <filename>os-release</filename> in + <citerefentry project='die-net'><refentrytitle>python</refentrytitle><manvolnum>1</manvolnum></citerefentry> (any version)</title> + + <programlisting><xi:include href="check-os-release.py" parse="text" /></programlisting> + + <para>Note that the above version that uses the built-in implementation is preferred + in most cases, and the open-coded version here is provided for reference.</para> + </example> + + </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> |