The /etc/os-release and /usr/lib/os-release files contain operating
system identification data.
The basic file format of os-release 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 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. Shell special characters ("$", quotes,
backslash, backtick) must be escaped with backslashes, following shell
style. All strings should be in UTF-8 format, and non-printable
characters should not be used. It is not supported to concatenate
multiple individually quoted strings. Lines beginning with "#" shall be
ignored as comments.
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
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.
For a longer rationale for os-release please refer to the Announcement
The following OS identifications parameters may be set using
A string identifying the operating system, without a version
component, and suitable for presentation to the user. If not set,
any version information and suitable for processing by scripts or
usage in generated filenames. If not set, defaults to "ID=linux".
Example: "ID=fedora" or "ID=debian".
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. Example: 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.
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: "VERSION_ID=17" or
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 "PRETTY_NAME="Linux"". Example: "PRETTY_NAME="Fedora 17 (Beefy
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: "ANSI_COLOR="0;31"" for
red, or "ANSI_COLOR="1;34"" for light blue.
A CPE name for the operating system, in URI binding syntax,
following the Common Platform Enumeration Specification as
proposed by the NIST. This field is optional. Example:
HOME_URL=, SUPPORT_URL=, BUG_REPORT_URL=, PRIVACY_POLICY_URL=
Links to resources on the Internet related the operating system.
HOME_URL= should refer to the homepage of the operating system, or
alternatively some homepage of the specific version of the
format, 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/"" and
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:
"BUILD_ID="2013-03-20.3"" or "BUILD_ID=201303203".
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.
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:
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
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:
1. Announcement of /etc/os-release
2. Common Platform Enumeration Specification
3. RFC3986 format
systemd 229 OS-RELEASE(5)
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