Provided by: systemd_252.5-2ubuntu3_amd64 bug

NAME

       os-release, initrd-release, extension-release - Operating system identification

SYNOPSIS

       /etc/os-release

       /usr/lib/os-release

       /etc/initrd-release

       /usr/lib/extension-release.d/extension-release.IMAGE

DESCRIPTION

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

       The format of os-release 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.

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

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

       As this file only encodes names and identifiers it should not be localized.

       The /etc/os-release and /usr/lib/os-release 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.

       os-release 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.

       For a longer rationale for os-release please refer to the Announcement of
       /etc/os-release[1].

   /etc/initrd-release
       In the initrd[2], /etc/initrd-release plays the same role as os-release in the main
       system. Additionally, the presence of that file means that the system is in the initrd
       phase.  /etc/os-release should be symlinked to /etc/initrd-release (or vice versa), so
       programs that only look for /etc/os-release (as described above) work correctly.

       The rest of this document that talks about os-release should be understood to apply to
       initrd-release too.

   /usr/lib/extension-release.d/extension-release.IMAGE
       /usr/lib/extension-release.d/extension-release.IMAGE plays the same role for extension
       images as os-release for the main system, and follows the syntax and rules as described in
       the Portable Services Documentation[3]. 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 ID= options match, and either
       SYSEXT_LEVEL= exists and matches too, or if it is not present, VERSION_ID= exists and
       matches. This ensures ABI/API compatibility between the layers and prevents merging of an
       incompatible image in an overlay.

       In the extension-release.IMAGE filename, the IMAGE 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
       "extension-release.*"  is present in this directory, and the file is tagged with a
       user.extension-release.strict xattr(7) set to the string "0", it will be used instead.

       The rest of this document that talks about os-release should be understood to apply to
       extension-release too.

OPTIONS

       The following OS identifications parameters may be set using os-release:

   General information identifying the operating system
       NAME=
           A string identifying the operating system, without a version component, and suitable
           for presentation to the user. If not set, a default of "NAME=Linux" may be used.

           Examples: "NAME=Fedora", "NAME="Debian GNU/Linux"".

       ID=
           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
           "ID=linux" may be used. Note that even though this string may not include characters
           that require shell quoting, quoting may nevertheless be used.

           Examples: "ID=fedora", "ID=debian".

       ID_LIKE=
           A space-separated list of operating system identifiers in the same syntax as the ID=
           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 ID= 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.

           Examples: for an operating system with "ID=centos", an assignment of "ID_LIKE="rhel
           fedora"" would be appropriate. For an operating system with "ID=ubuntu", an assignment
           of "ID_LIKE=debian" is appropriate.

       PRETTY_NAME=
           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 "PRETTY_NAME="Linux"" may be used

           Example: "PRETTY_NAME="Fedora 17 (Beefy Miracle)"".

       CPE_NAME=
           A CPE name for the operating system, in URI binding syntax, following the Common
           Platform Enumeration Specification[4] as proposed by the NIST. This field is optional.

           Example: "CPE_NAME="cpe:/o:fedoraproject:fedora:17""

       VARIANT=
           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: "VARIANT="Server Edition"", "VARIANT="Smart Refrigerator Edition"".

           Note: this field is for display purposes only. The VARIANT_ID field should be used for
           making programmatic decisions.

       VARIANT_ID=
           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: "VARIANT_ID=server", "VARIANT_ID=embedded".

   Information about the version of the operating system
       VERSION=
           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.

           Examples: "VERSION=17", "VERSION="17 (Beefy Miracle)"".

       VERSION_ID=
           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.

           Examples: "VERSION_ID=17", "VERSION_ID=11.04".

       VERSION_CODENAME=
           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: "VERSION_CODENAME=buster", "VERSION_CODENAME=xenial".

       BUILD_ID=
           A string uniquely identifying the system image originally used as the installation
           base. In most cases, VERSION_ID or IMAGE_ID+IMAGE_VERSION are updated when the entire
           system image is replaced during an update.  BUILD_ID may be used in distributions
           where the original installation image version is important: VERSION_ID would change
           during incremental system updates, but BUILD_ID would not. This field is optional.

           Examples: "BUILD_ID="2013-03-20.3"", "BUILD_ID=201303203".

       IMAGE_ID=
           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.

           Examples: "IMAGE_ID=vendorx-cashier-system", "IMAGE_ID=netbook-image".

       IMAGE_VERSION=
           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 IMAGE_ID described above, to discern different versions of the same
           image.

           Examples: "IMAGE_VERSION=33", "IMAGE_VERSION=47.1rc1".

       To summarize: if the image updates are built and shipped as comprehensive units,
       IMAGE_ID+IMAGE_VERSION is the best fit. Otherwise, if updates eventually completely
       replace previously installed contents, as in a typical binary distribution, VERSION_ID
       should be used to identify major releases of the operating system.  BUILD_ID may be used
       instead or in addition to VERSION_ID when the original system image version is important.

   Presentation information and links
       HOME_URL=, DOCUMENTATION_URL=, SUPPORT_URL=, BUG_REPORT_URL=, PRIVACY_POLICY_URL=
           Links to resources on the Internet related to the operating system.  HOME_URL= should
           refer to the homepage of the operating system, or alternatively some homepage of the
           specific version of the operating system.  DOCUMENTATION_URL= should refer to the main
           documentation page for this operating system.  SUPPORT_URL= 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.  BUG_REPORT_URL= 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.
           PRIVACY_POLICY_URL= 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 RFC3986 format[5], and
           should be "http:" or "https:" URLs, and possibly "mailto:" or "tel:". 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: "HOME_URL="https://fedoraproject.org/"",
           "BUG_REPORT_URL="https://bugzilla.redhat.com/"".

       SUPPORT_END=
           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 "YYYY-MM-DD", and specifies the first day on which support is not provided.

           For example, "SUPPORT_END=2001-01-01" means that the system was supported until the
           end of the last day of the previous millennium.

       LOGO=
           A string, specifying the name of an icon as defined by freedesktop.org Icon Theme
           Specification[6]. 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: "LOGO=fedora-logo", "LOGO=distributor-logo-opensuse"

       ANSI_COLOR=
           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.

           Examples: "ANSI_COLOR="0;31"" for red, "ANSI_COLOR="1;34"" for light blue, or
           "ANSI_COLOR="0;38;2;60;110;180"" for Fedora blue.

   Distribution-level defaults and metadata
       DEFAULT_HOSTNAME=
           A string specifying the hostname if hostname(5) 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).

           See org.freedesktop.hostname1(5) for a description of how systemd-hostnamed.service(8)
           determines the fallback hostname.

       ARCHITECTURE=
           A string that specifies which CPU architecture the userspace binaries require. The
           architecture identifiers are the same as for ConditionArchitecture= described in
           systemd.unit(5). 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.

       SYSEXT_LEVEL=
           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
           /usr/lib/extension-release.d/extension-release.IMAGE, initrd[2] and systemd-sysext(8))
           for more information.

           Examples: "SYSEXT_LEVEL=2", "SYSEXT_LEVEL=15.14".

       SYSEXT_SCOPE=
           Takes a space-separated list of one or more of the strings "system", "initrd" and
           "portable". This field is only supported in extension-release.d/ 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, "SYSEXT_SCOPE=system portable"
           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.

       PORTABLE_PREFIXES=
           Takes a space-separated list of one or more valid prefix match strings for the
           Portable Services[3] 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.

   Notes
       If you are using this file 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.

       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.

       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: "DEBIAN_BTS="debbugs://bugs.debian.org/"".

       Container and sandbox runtime managers may make the host's identification data available
       to applications by providing the host's /etc/os-release (if available, otherwise
       /usr/lib/os-release as a fallback) as /run/host/os-release.

EXAMPLES

       Example 1. os-release file for Fedora Workstation

           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

       Example 2. extension-release file for an extension for Fedora Workstation 32

           ID=fedora
           VERSION_ID=32

       Example 3. Reading os-release in sh(1)

           #!/bin/sh -eu
           # SPDX-License-Identifier: MIT-0

           test -e /etc/os-release && os_release='/etc/os-release' || os_release='/usr/lib/os-release'
           . "${os_release}"

           echo "Running on ${PRETTY_NAME:-Linux}"

           if [ "${ID:-linux}" = "debian" ] || [ "${ID_LIKE#*debian*}" != "${ID_LIKE}" ]; then
               echo "Looks like Debian!"
           fi

       Example 4. Reading os-release in python(1) (versions >= 3.10)

           #!/usr/bin/python
           # SPDX-License-Identifier: MIT-0

           import platform
           os_release = platform.freedesktop_os_release()

           pretty_name = os_release.get('PRETTY_NAME', 'Linux')
           print(f'Running on {pretty_name!r}')

           if 'fedora' in [os_release.get('ID', 'linux'),
                           *os_release.get('ID_LIKE', '').split()]:
               print('Looks like Fedora!')

       See docs for platform.freedesktop_os_release[7] for more details.

       Example 5. Reading os-release in python(1) (any version)

           #!/usr/bin/python
           # SPDX-License-Identifier: MIT-0

           import ast
           import re
           import sys

           def read_os_release():
               try:
                   filename = '/etc/os-release'
                   f = open(filename)
               except FileNotFoundError:
                   filename = '/usr/lib/os-release'
                   f = open(filename)

               for line_number, line in enumerate(f, start=1):
                   line = line.rstrip()
                   if not line or line.startswith('#'):
                       continue
                   m = re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line)
                   if m:
                       name, val = m.groups()
                       if val and val[0] in '"\'':
                           val = ast.literal_eval(val)
                       yield name, val
                   else:
                       print(f'{filename}:{line_number}: bad line {line!r}',
                             file=sys.stderr)

           os_release = dict(read_os_release())

           pretty_name = os_release.get('PRETTY_NAME', 'Linux')
           print(f'Running on {pretty_name!r}')

           if 'debian' in [os_release.get('ID', 'linux'),
                           *os_release.get('ID_LIKE', '').split()]:
               print('Looks like Debian!')

       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.

SEE ALSO

       systemd(1), lsb_release(1), hostname(5), machine-id(5), machine-info(5)

NOTES

        1. Announcement of /etc/os-release
           http://0pointer.de/blog/projects/os-release

        2. initrd
           https://docs.kernel.org/admin-guide/initrd.html

        3. Portable Services Documentation
           https://systemd.io/PORTABLE_SERVICES

        4. Common Platform Enumeration Specification
           http://scap.nist.gov/specifications/cpe/

        5. RFC3986 format
           https://tools.ietf.org/html/rfc3986

        6. freedesktop.org Icon Theme Specification
           https://standards.freedesktop.org/icon-theme-spec/latest

        7.

                 platform.freedesktop_os_release
           https://docs.python.org/3/library/platform.html#platform.freedesktop_os_release