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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | SEE ALSO | NOTES | COLOPHON |
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OS-RELEASE(5) os-release OS-RELEASE(5)
os-release, initrd-release, extension-release - Operating system
identification
/etc/os-release
/usr/lib/os-release
/etc/initrd-release
/usr/lib/extension-release.d/extension-release.IMAGE
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.
[1m/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[3] 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 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 order to identify the extension image itself, the same fields
defined below can be added to the extension-release file with a
SYSEXT_ prefix (to disambiguate from fields used to match on the
base image). E.g.: SYSEXT_ID=myext, SYSEXT_VERSION_ID=1.2.3.
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.
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.
Added in version 220.
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".
Added in version 220.
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".
Added in version 231.
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".
Added in version 200.
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".
Added in version 249.
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".
Added in version 249.
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.
Added in version 252.
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"
Added in version 240.
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.
VENDOR_NAME=
The name of the OS vendor. This is the name of the
organization or company which produces the OS. This field is
optional.
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.
Examples: "VENDOR_NAME="Fedora Project"" for Fedora Linux,
"VENDOR_NAME="Canonical"" for Ubuntu.
Added in version 254.
VENDOR_URL=
The homepage of the OS vendor. This field is optional. The
VENDOR_NAME= field should be set if this one is, although
clients must be robust against either field not being set.
The value should be in RFC3986 format[5], and should be
"http:" or "https:" URLs. Only one URL shall be listed in the
setting.
Examples: "VENDOR_URL="https://fedoraproject.org/"",
"VENDOR_URL="https://canonical.com/"".
Added in version 254.
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.
Added in version 248.
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.
Added in version 252.
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".
Added in version 248.
CONFEXT_LEVEL=
Semantically the same as SYSEXT_LEVEL= but for confext
images. See /etc/extension-release.d/extension-release.IMAGE
for more information.
Examples: "CONFEXT_LEVEL=2", "CONFEXT_LEVEL=15.14".
Added in version 254.
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.
Added in version 250.
CONFEXT_SCOPE=
Semantically the same as SYSEXT_SCOPE= but for confext
images.
Added in version 254.
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.
Added in version 250.
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.
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.
systemd(1), lsb_release(1), hostname(5), machine-id(5),
machine-info(5)
1. Announcement of /etc/os-release
https://0pointer.de/blog/projects/os-release
2. initrd
https://docs.kernel.org/admin-guide/initrd.html
3. Portable Services
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
This page is part of the systemd (systemd system and service
manager) project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have
a bug report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/systemd/systemd.git⟩ on 2023-12-22. (At that
time, the date of the most recent commit that was found in the
repository was 2023-12-22.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 255 OS-RELEASE(5)
Pages that refer to this page: portablectl(1), systemd-dissect(1), systemd-nspawn(1), ukify(1), dnf.conf(5), locale.conf(5), machine-id(5), machine-info(5), org.freedesktop.hostname1(5), org.freedesktop.machine1(5), org.freedesktop.portable1(5), org.freedesktop.systemd1(5), repart.d(5), systemd.dnssd(5), systemd.exec(5), systemd-system.conf(5), systemd.unit(5), sysupdate.d(5), sysusers.d(5), tmpfiles.d(5), vconsole.conf(5), yum.conf(5), systemd.directives(7), systemd.index(7), kernel-install(8)
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HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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