1OS-RELEASE(5) os-release OS-RELEASE(5)
2
6 os-release, initrd-release, extension-release - Operating system
7 identification
8
10 /etc/os-release
11 /usr/lib/os-release
13 /etc/initrd-release
15 /usr/lib/extension-release.d/extension-release.IMAGE
17
19 The /etc/os-release and /usr/lib/os-release files contain operating
20 system identification data.
21 The format of os-release is a newline-separated list of
23 environment-like shell-compatible variable assignments. It is possible
24 to source the configuration from Bourne shell scripts, however, beyond
25 mere variable assignments, no shell features are supported (this means
26 variable expansion is explicitly not supported), allowing applications
27 to read the file without implementing a shell compatible execution
28 engine. Variable assignment values must be enclosed in double or single
29 quotes if they include spaces, semicolons or other special characters
30 outside of A–Z, a–z, 0–9. (Assignments that do not include these
31 special characters may be enclosed in quotes too, but this is
32 optional.) Shell special characters ("$", quotes, backslash, backtick)
33 must be escaped with backslashes, following shell style. All strings
34 should be in UTF-8 encoding, and non-printable characters should not be
35 used. Concatenation of multiple individually quoted strings is not
36 supported. Lines beginning with "#" are treated as comments. Blank
37 lines are permitted and ignored.
38 The file /etc/os-release takes precedence over /usr/lib/os-release.
40 Applications should check for the former, and exclusively use its data
41 if it exists, and only fall back to /usr/lib/os-release if it is
42 missing. Applications should not read data from both files at the same
43 time. /usr/lib/os-release is the recommended place to store OS release
44 information as part of vendor trees. /etc/os-release should be a
45 relative symlink to /usr/lib/os-release, to provide compatibility with
46 applications only looking at /etc/. A relative symlink instead of an
47 absolute symlink is necessary to avoid breaking the link in a chroot or
48 initrd environment such as dracut.
49 os-release contains data that is defined by the operating system vendor
51 and should generally not be changed by the administrator.
52 As this file only encodes names and identifiers it should not be
54 localized.
55 The /etc/os-release and /usr/lib/os-release files might be symlinks to
57 other files, but it is important that the file is available from
58 earliest boot on, and hence must be located on the root file system.
59 os-release must not contain repeating keys. Nevertheless, readers
61 should pick the entries later in the file in case of repeats, similarly
62 to how a shell sourcing the file would. A reader may warn about
63 repeating entries.
64 For a longer rationale for os-release please refer to the Announcement
66 of /etc/os-release[1].
67 /etc/initrd-release
69 In the initrd[2], /etc/initrd-release plays the same role as os-release
70 in the main system. Additionally, the presence of that file means that
71 the system is in the initrd phase. /etc/os-release should be symlinked
72 to /etc/initrd-release (or vice versa), so programs that only look for
73 /etc/os-release (as described above) work correctly.
74 The rest of this document that talks about os-release should be
76 understood to apply to initrd-release too.
77 /usr/lib/extension-release.d/extension-release.IMAGE
79 /usr/lib/extension-release.d/extension-release.IMAGE plays the same
80 role for extension images as os-release for the main system, and
81 follows the syntax and rules as described in the Portable Services
82 Documentation[3]. The purpose of this file is to identify the extension
83 and to allow the operating system to verify that the extension image
84 matches the base OS. This is typically implemented by checking that the
85 ID= options match, and either SYSEXT_LEVEL= exists and matches too, or
86 if it is not present, VERSION_ID= exists and matches. This ensures
87 ABI/API compatibility between the layers and prevents merging of an
88 incompatible image in an overlay.
89 In the extension-release.IMAGE filename, the IMAGE part must exactly
91 match the file name of the containing image with the suffix removed. In
92 case it is not possible to guarantee that an image file name is stable
93 and doesn't change between the build and the deployment phases, it is
94 possible to relax this check: if exactly one file whose name matches
95 "extension-release.*" is present in this directory, and the file is
96 tagged with a user.extension-release.strict xattr(7) set to the string
97 "0", it will be used instead.
98 The rest of this document that talks about os-release should be
100 understood to apply to extension-release too.
101
103 The following OS identifications parameters may be set using
104 os-release:
105 General information identifying the operating system
107 NAME=
108 A string identifying the operating system, without a version
109 component, and suitable for presentation to the user. If not set, a
110 default of "NAME=Linux" may be used.
111 Examples: "NAME=Fedora", "NAME="Debian GNU/Linux"".
113 ID=
115 A lower-case string (no spaces or other characters outside of 0–9,
116 a–z, ".", "_" and "-") identifying the operating system, excluding
117 any version information and suitable for processing by scripts or
118 usage in generated filenames. If not set, a default of "ID=linux"
119 may be used. Note that even though this string may not include
120 characters that require shell quoting, quoting may nevertheless be
121 used.
122 Examples: "ID=fedora", "ID=debian".
124 ID_LIKE=
126 A space-separated list of operating system identifiers in the same
127 syntax as the ID= setting. It should list identifiers of operating
128 systems that are closely related to the local operating system in
129 regards to packaging and programming interfaces, for example
130 listing one or more OS identifiers the local OS is a derivative
131 from. An OS should generally only list other OS identifiers it
132 itself is a derivative of, and not any OSes that are derived from
133 it, though symmetric relationships are possible. Build scripts and
134 similar should check this variable if they need to identify the
135 local operating system and the value of ID= is not recognized.
136 Operating systems should be listed in order of how closely the
137 local operating system relates to the listed ones, starting with
138 the closest. This field is optional.
139 Examples: for an operating system with "ID=centos", an assignment
141 of "ID_LIKE="rhel fedora"" would be appropriate. For an operating
142 system with "ID=ubuntu", an assignment of "ID_LIKE=debian" is
143 appropriate.
144 PRETTY_NAME=
146 A pretty operating system name in a format suitable for
147 presentation to the user. May or may not contain a release code
148 name or OS version of some kind, as suitable. If not set, a default
149 of "PRETTY_NAME="Linux"" may be used
150 Example: "PRETTY_NAME="Fedora 17 (Beefy Miracle)"".
152 CPE_NAME=
154 A CPE name for the operating system, in URI binding syntax,
155 following the Common Platform Enumeration Specification[4] as
156 proposed by the NIST. This field is optional.
157 Example: "CPE_NAME="cpe:/o:fedoraproject:fedora:17""
159 VARIANT=
161 A string identifying a specific variant or edition of the operating
162 system suitable for presentation to the user. This field may be
163 used to inform the user that the configuration of this system is
164 subject to a specific divergent set of rules or default
165 configuration settings. This field is optional and may not be
166 implemented on all systems.
167 Examples: "VARIANT="Server Edition"", "VARIANT="Smart Refrigerator
169 Edition"".
170 Note: this field is for display purposes only. The VARIANT_ID field
172 should be used for making programmatic decisions.
173 VARIANT_ID=
175 A lower-case string (no spaces or other characters outside of 0–9,
176 a–z, ".", "_" and "-"), identifying a specific variant or edition
177 of the operating system. This may be interpreted by other packages
178 in order to determine a divergent default configuration. This field
179 is optional and may not be implemented on all systems.
180 Examples: "VARIANT_ID=server", "VARIANT_ID=embedded".
182 Information about the version of the operating system
184 VERSION=
185 A string identifying the operating system version, excluding any OS
186 name information, possibly including a release code name, and
187 suitable for presentation to the user. This field is optional.
188 Examples: "VERSION=17", "VERSION="17 (Beefy Miracle)"".
190 VERSION_ID=
192 A lower-case string (mostly numeric, no spaces or other characters
193 outside of 0–9, a–z, ".", "_" and "-") identifying the operating
194 system version, excluding any OS name information or release code
195 name, and suitable for processing by scripts or usage in generated
196 filenames. This field is optional.
197 Examples: "VERSION_ID=17", "VERSION_ID=11.04".
199 VERSION_CODENAME=
201 A lower-case string (no spaces or other characters outside of 0–9,
202 a–z, ".", "_" and "-") identifying the operating system release
203 code name, excluding any OS name information or release version,
204 and suitable for processing by scripts or usage in generated
205 filenames. This field is optional and may not be implemented on all
206 systems.
207 Examples: "VERSION_CODENAME=buster", "VERSION_CODENAME=xenial".
209 BUILD_ID=
211 A string uniquely identifying the system image originally used as
212 the installation base. In most cases, VERSION_ID or
213 IMAGE_ID+IMAGE_VERSION are updated when the entire system image is
214 replaced during an update. BUILD_ID may be used in distributions
215 where the original installation image version is important:
216 VERSION_ID would change during incremental system updates, but
217 BUILD_ID would not. This field is optional.
218 Examples: "BUILD_ID="2013-03-20.3"", "BUILD_ID=201303203".
220 IMAGE_ID=
222 A lower-case string (no spaces or other characters outside of 0–9,
223 a–z, ".", "_" and "-"), identifying a specific image of the
224 operating system. This is supposed to be used for environments
225 where OS images are prepared, built, shipped and updated as
226 comprehensive, consistent OS images. This field is optional and may
227 not be implemented on all systems, in particularly not on those
228 that are not managed via images but put together and updated from
229 individual packages and on the local system.
230 Examples: "IMAGE_ID=vendorx-cashier-system",
232 "IMAGE_ID=netbook-image".
233 IMAGE_VERSION=
235 A lower-case string (mostly numeric, no spaces or other characters
236 outside of 0–9, a–z, ".", "_" and "-") identifying the OS image
237 version. This is supposed to be used together with IMAGE_ID
238 described above, to discern different versions of the same image.
239 Examples: "IMAGE_VERSION=33", "IMAGE_VERSION=47.1rc1".
241 To summarize: if the image updates are built and shipped as
243 comprehensive units, IMAGE_ID+IMAGE_VERSION is the best fit. Otherwise,
244 if updates eventually completely replace previously installed contents,
245 as in a typical binary distribution, VERSION_ID should be used to
246 identify major releases of the operating system. BUILD_ID may be used
247 instead or in addition to VERSION_ID when the original system image
248 version is important.
249 Presentation information and links
251 HOME_URL=, DOCUMENTATION_URL=, SUPPORT_URL=, BUG_REPORT_URL=,
252 PRIVACY_POLICY_URL=
253 Links to resources on the Internet related to the operating system.
254 HOME_URL= should refer to the homepage of the operating system, or
255 alternatively some homepage of the specific version of the
256 operating system. DOCUMENTATION_URL= should refer to the main
257 documentation page for this operating system. SUPPORT_URL= should
258 refer to the main support page for the operating system, if there
259 is any. This is primarily intended for operating systems which
260 vendors provide support for. BUG_REPORT_URL= should refer to the
261 main bug reporting page for the operating system, if there is any.
262 This is primarily intended for operating systems that rely on
263 community QA. PRIVACY_POLICY_URL= should refer to the main privacy
264 policy page for the operating system, if there is any. These
265 settings are optional, and providing only some of these settings is
266 common. These URLs are intended to be exposed in "About this
267 system" UIs behind links with captions such as "About this
268 Operating System", "Obtain Support", "Report a Bug", or "Privacy
269 Policy". The values should be in RFC3986 format[5], and should be
270 "http:" or "https:" URLs, and possibly "mailto:" or "tel:". Only
271 one URL shall be listed in each setting. If multiple resources need
272 to be referenced, it is recommended to provide an online landing
273 page linking all available resources.
274 Examples: "HOME_URL="https://fedoraproject.org/"",
276 "BUG_REPORT_URL="https://bugzilla.redhat.com/"".
277 LOGO=
279 A string, specifying the name of an icon as defined by
280 freedesktop.org Icon Theme Specification[6]. This can be used by
281 graphical applications to display an operating system's or
282 distributor's logo. This field is optional and may not necessarily
283 be implemented on all systems.
284 Examples: "LOGO=fedora-logo", "LOGO=distributor-logo-opensuse"
286 ANSI_COLOR=
288 A suggested presentation color when showing the OS name on the
289 console. This should be specified as string suitable for inclusion
290 in the ESC [ m ANSI/ECMA-48 escape code for setting graphical
291 rendition. This field is optional.
292 Examples: "ANSI_COLOR="0;31"" for red, "ANSI_COLOR="1;34"" for
294 light blue, or "ANSI_COLOR="0;38;2;60;110;180"" for Fedora blue.
295 Distribution-level defaults and metadata
297 DEFAULT_HOSTNAME=
298 A string specifying the hostname if hostname(5) is not present and
299 no other configuration source specifies the hostname. Must be
300 either a single DNS label (a string composed of 7-bit ASCII
301 lower-case characters and no spaces or dots, limited to the format
302 allowed for DNS domain name labels), or a sequence of such labels
303 separated by single dots that forms a valid DNS FQDN. The hostname
304 must be at most 64 characters, which is a Linux limitation (DNS
305 allows longer names).
306 See org.freedesktop.hostname1(5) for a description of how systemd-
308 hostnamed.service(8) determines the fallback hostname.
309 SYSEXT_LEVEL=
311 A lower-case string (mostly numeric, no spaces or other characters
312 outside of 0–9, a–z, ".", "_" and "-") identifying the operating
313 system extensions support level, to indicate which extension images
314 are supported. See
315 /usr/lib/extension-release.d/extension-release.IMAGE, initrd[2] and
316 systemd-sysext(8)) for more information.
317 Examples: "SYSEXT_LEVEL=2", "SYSEXT_LEVEL=15.14".
319 SYSEXT_SCOPE=
321 Takes a space-separated list of one or more of the strings
322 "system", "initrd" and "portable". This field is only supported in
323 extension-release.d/ files and indicates what environments the
324 system extension is applicable to: i.e. to regular systems, to
325 initial RAM filesystems ("initrd") or to portable service images.
326 If unspecified, "SYSEXT_SCOPE=system portable" is implied, i.e. any
327 system extension without this field is applicable to regular
328 systems and to portable service environments, but not to initrd
329 environments.
330 PORTABLE_PREFIXES=
332 Takes a space-separated list of one or more valid prefix match
333 strings for the Portable Services[3] logic. This field serves two
334 purposes: it is informational, identifying portable service images
335 as such (and thus allowing them to be distinguished from other OS
336 images, such as bootable system images). It is also used when a
337 portable service image is attached: the specified or implied
338 portable service prefix is checked against the list specified here,
339 to enforce restrictions how images may be attached to a system.
340 Notes
342 If you are using this file to determine the OS or a specific version of
343 it, use the ID and VERSION_ID fields, possibly with ID_LIKE as fallback
344 for ID. When looking for an OS identification string for presentation
345 to the user use the PRETTY_NAME field.
346 Note that operating system vendors may choose not to provide version
348 information, for example to accommodate for rolling releases. In this
349 case, VERSION and VERSION_ID may be unset. Applications should not rely
350 on these fields to be set.
351 Operating system vendors may extend the file format and introduce new
353 fields. It is highly recommended to prefix new fields with an OS
354 specific name in order to avoid name clashes. Applications reading this
355 file must ignore unknown fields.
356 Example: "DEBIAN_BTS="debbugs://bugs.debian.org/"".
358 Container and sandbox runtime managers may make the host's
360 identification data available to applications by providing the host's
361 /etc/os-release (if available, otherwise /usr/lib/os-release as a
362 fallback) as /run/host/os-release.
363
365 Example 1. os-release file for Fedora Workstation
366 NAME=Fedora
368 VERSION="32 (Workstation Edition)"
369 ID=fedora
370 VERSION_ID=32
371 PRETTY_NAME="Fedora 32 (Workstation Edition)"
372 ANSI_COLOR="0;38;2;60;110;180"
373 LOGO=fedora-logo-icon
374 CPE_NAME="cpe:/o:fedoraproject:fedora:32"
375 HOME_URL="https://fedoraproject.org/"
376 DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f32/system-administrators-guide/"
377 SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
378 BUG_REPORT_URL="https://bugzilla.redhat.com/"
379 REDHAT_BUGZILLA_PRODUCT="Fedora"
380 REDHAT_BUGZILLA_PRODUCT_VERSION=32
381 REDHAT_SUPPORT_PRODUCT="Fedora"
382 REDHAT_SUPPORT_PRODUCT_VERSION=32
383 PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
384 VARIANT="Workstation Edition"
385 VARIANT_ID=workstation
386 Example 2. extension-release file for an extension for Fedora
388 Workstation 32
389 ID=fedora
391 VERSION_ID=32
392 Example 3. Reading os-release in sh(1)
394 #!/bin/sh -eu
396 # SPDX-License-Identifier: CC0-1.0
397 test -e /etc/os-release && os_release='/etc/os-release' || os_release='/usr/lib/os-release'
399 . "${os_release}"
400 echo "Running on ${PRETTY_NAME:-Linux}"
402 if [ "${ID:-linux}" = "debian" ] || [ "${ID_LIKE#*debian*}" != "${ID_LIKE}" ]; then
404 echo "Looks like Debian!"
405 fi
406 Example 4. Reading os-release in python(1) (versions >= 3.10)
408 #!/usr/bin/python
410 # SPDX-License-Identifier: CC0-1.0
411 import platform
413 os_release = platform.freedesktop_os_release()
414 pretty_name = os_release.get('PRETTY_NAME', 'Linux')
416 print(f'Running on {pretty_name!r}')
417 if 'fedora' in [os_release.get('ID', 'linux'),
419 *os_release.get('ID_LIKE', '').split()]:
420 print('Looks like Fedora!')
421 See docs for platform.freedesktop_os_release[7] for more details.
423 Example 5. Reading os-release in python(1) (any version)
425 #!/usr/bin/python
427 # SPDX-License-Identifier: CC0-1.0
428 import ast
430 import re
431 import sys
432 def read_os_release():
434 try:
435 filename = '/etc/os-release'
436 f = open(filename)
437 except FileNotFoundError:
438 filename = '/usr/lib/os-release'
439 f = open(filename)
440 for line_number, line in enumerate(f, start=1):
442 line = line.rstrip()
443 if not line or line.startswith('#'):
444 continue
445 m = re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line)
446 if m:
447 name, val = m.groups()
448 if val and val[0] in '"\'':
449 val = ast.literal_eval(val)
450 yield name, val
451 else:
452 print(f'{filename}:{line_number}: bad line {line!r}',
453 file=sys.stderr)
454 os_release = dict(read_os_release())
456 pretty_name = os_release.get('PRETTY_NAME', 'Linux')
458 print(f'Running on {pretty_name!r}')
459 if 'debian' in [os_release.get('ID', 'linux'),
461 *os_release.get('ID_LIKE', '').split()]:
462 print('Looks like Debian!')
463 Note that the above version that uses the built-in implementation is
465 preferred in most cases, and the open-coded version here is provided
466 for reference.
467
469 systemd(1), lsb_release(1), hostname(5), machine-id(5), machine-info(5)
470
472 1. Announcement of /etc/os-release
473 http://0pointer.de/blog/projects/os-release
474 2. initrd
476 https://www.kernel.org/doc/html/latest/admin-guide/initrd.html
477 3. Portable Services Documentation
479 https://systemd.io/PORTABLE_SERVICES
480 4. Common Platform Enumeration Specification
482 http://scap.nist.gov/specifications/cpe/
483 5. RFC3986 format
485 https://tools.ietf.org/html/rfc3986
486 6. freedesktop.org Icon Theme Specification
488 http://standards.freedesktop.org/icon-theme-spec/latest
489 7.
491 platform.freedesktop_os_release
493 https://docs.python.org/3/library/platform.html#platform.freedesktop_os_release
494systemd 251 OS-RELEASE(5)