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 order to identify the extension image itself, the same fields
91 defined below can be added to the extension-release file with a SYSEXT_
92 prefix (to disambiguate from fields used to match on the base image).
93 E.g.: SYSEXT_ID=myext, SYSEXT_VERSION_ID=1.2.3.
94 In the extension-release.IMAGE filename, the IMAGE part must exactly
96 match the file name of the containing image with the suffix removed. In
97 case it is not possible to guarantee that an image file name is stable
98 and doesn't change between the build and the deployment phases, it is
99 possible to relax this check: if exactly one file whose name matches
100 "extension-release.*" is present in this directory, and the file is
101 tagged with a user.extension-release.strict xattr(7) set to the string
102 "0", it will be used instead.
103 The rest of this document that talks about os-release should be
105 understood to apply to extension-release too.
106
108 The following OS identifications parameters may be set using
109 os-release:
110 General information identifying the operating system
112 NAME=
113 A string identifying the operating system, without a version
114 component, and suitable for presentation to the user. If not set, a
115 default of "NAME=Linux" may be used.
116 Examples: "NAME=Fedora", "NAME="Debian GNU/Linux"".
118 ID=
120 A lower-case string (no spaces or other characters outside of 0–9,
121 a–z, ".", "_" and "-") identifying the operating system, excluding
122 any version information and suitable for processing by scripts or
123 usage in generated filenames. If not set, a default of "ID=linux"
124 may be used. Note that even though this string may not include
125 characters that require shell quoting, quoting may nevertheless be
126 used.
127 Examples: "ID=fedora", "ID=debian".
129 ID_LIKE=
131 A space-separated list of operating system identifiers in the same
132 syntax as the ID= setting. It should list identifiers of operating
133 systems that are closely related to the local operating system in
134 regards to packaging and programming interfaces, for example
135 listing one or more OS identifiers the local OS is a derivative
136 from. An OS should generally only list other OS identifiers it
137 itself is a derivative of, and not any OSes that are derived from
138 it, though symmetric relationships are possible. Build scripts and
139 similar should check this variable if they need to identify the
140 local operating system and the value of ID= is not recognized.
141 Operating systems should be listed in order of how closely the
142 local operating system relates to the listed ones, starting with
143 the closest. This field is optional.
144 Examples: for an operating system with "ID=centos", an assignment
146 of "ID_LIKE="rhel fedora"" would be appropriate. For an operating
147 system with "ID=ubuntu", an assignment of "ID_LIKE=debian" is
148 appropriate.
149 PRETTY_NAME=
151 A pretty operating system name in a format suitable for
152 presentation to the user. May or may not contain a release code
153 name or OS version of some kind, as suitable. If not set, a default
154 of "PRETTY_NAME="Linux"" may be used
155 Example: "PRETTY_NAME="Fedora 17 (Beefy Miracle)"".
157 CPE_NAME=
159 A CPE name for the operating system, in URI binding syntax,
160 following the Common Platform Enumeration Specification[4] as
161 proposed by the NIST. This field is optional.
162 Example: "CPE_NAME="cpe:/o:fedoraproject:fedora:17""
164 VARIANT=
166 A string identifying a specific variant or edition of the operating
167 system suitable for presentation to the user. This field may be
168 used to inform the user that the configuration of this system is
169 subject to a specific divergent set of rules or default
170 configuration settings. This field is optional and may not be
171 implemented on all systems.
172 Examples: "VARIANT="Server Edition"", "VARIANT="Smart Refrigerator
174 Edition"".
175 Note: this field is for display purposes only. The VARIANT_ID field
177 should be used for making programmatic decisions.
178 VARIANT_ID=
180 A lower-case string (no spaces or other characters outside of 0–9,
181 a–z, ".", "_" and "-"), identifying a specific variant or edition
182 of the operating system. This may be interpreted by other packages
183 in order to determine a divergent default configuration. This field
184 is optional and may not be implemented on all systems.
185 Examples: "VARIANT_ID=server", "VARIANT_ID=embedded".
187 Information about the version of the operating system
189 VERSION=
190 A string identifying the operating system version, excluding any OS
191 name information, possibly including a release code name, and
192 suitable for presentation to the user. This field is optional.
193 Examples: "VERSION=17", "VERSION="17 (Beefy Miracle)"".
195 VERSION_ID=
197 A lower-case string (mostly numeric, no spaces or other characters
198 outside of 0–9, a–z, ".", "_" and "-") identifying the operating
199 system version, excluding any OS name information or release code
200 name, and suitable for processing by scripts or usage in generated
201 filenames. This field is optional.
202 Examples: "VERSION_ID=17", "VERSION_ID=11.04".
204 VERSION_CODENAME=
206 A lower-case string (no spaces or other characters outside of 0–9,
207 a–z, ".", "_" and "-") identifying the operating system release
208 code name, excluding any OS name information or release version,
209 and suitable for processing by scripts or usage in generated
210 filenames. This field is optional and may not be implemented on all
211 systems.
212 Examples: "VERSION_CODENAME=buster", "VERSION_CODENAME=xenial".
214 BUILD_ID=
216 A string uniquely identifying the system image originally used as
217 the installation base. In most cases, VERSION_ID or
218 IMAGE_ID+IMAGE_VERSION are updated when the entire system image is
219 replaced during an update. BUILD_ID may be used in distributions
220 where the original installation image version is important:
221 VERSION_ID would change during incremental system updates, but
222 BUILD_ID would not. This field is optional.
223 Examples: "BUILD_ID="2013-03-20.3"", "BUILD_ID=201303203".
225 IMAGE_ID=
227 A lower-case string (no spaces or other characters outside of 0–9,
228 a–z, ".", "_" and "-"), identifying a specific image of the
229 operating system. This is supposed to be used for environments
230 where OS images are prepared, built, shipped and updated as
231 comprehensive, consistent OS images. This field is optional and may
232 not be implemented on all systems, in particularly not on those
233 that are not managed via images but put together and updated from
234 individual packages and on the local system.
235 Examples: "IMAGE_ID=vendorx-cashier-system",
237 "IMAGE_ID=netbook-image".
238 IMAGE_VERSION=
240 A lower-case string (mostly numeric, no spaces or other characters
241 outside of 0–9, a–z, ".", "_" and "-") identifying the OS image
242 version. This is supposed to be used together with IMAGE_ID
243 described above, to discern different versions of the same image.
244 Examples: "IMAGE_VERSION=33", "IMAGE_VERSION=47.1rc1".
246 To summarize: if the image updates are built and shipped as
248 comprehensive units, IMAGE_ID+IMAGE_VERSION is the best fit. Otherwise,
249 if updates eventually completely replace previously installed contents,
250 as in a typical binary distribution, VERSION_ID should be used to
251 identify major releases of the operating system. BUILD_ID may be used
252 instead or in addition to VERSION_ID when the original system image
253 version is important.
254 Presentation information and links
256 HOME_URL=, DOCUMENTATION_URL=, SUPPORT_URL=, BUG_REPORT_URL=,
257 PRIVACY_POLICY_URL=
258 Links to resources on the Internet related to the operating system.
259 HOME_URL= should refer to the homepage of the operating system, or
260 alternatively some homepage of the specific version of the
261 operating system. DOCUMENTATION_URL= should refer to the main
262 documentation page for this operating system. SUPPORT_URL= should
263 refer to the main support page for the operating system, if there
264 is any. This is primarily intended for operating systems which
265 vendors provide support for. BUG_REPORT_URL= should refer to the
266 main bug reporting page for the operating system, if there is any.
267 This is primarily intended for operating systems that rely on
268 community QA. PRIVACY_POLICY_URL= should refer to the main privacy
269 policy page for the operating system, if there is any. These
270 settings are optional, and providing only some of these settings is
271 common. These URLs are intended to be exposed in "About this
272 system" UIs behind links with captions such as "About this
273 Operating System", "Obtain Support", "Report a Bug", or "Privacy
274 Policy". The values should be in RFC3986 format[5], and should be
275 "http:" or "https:" URLs, and possibly "mailto:" or "tel:". Only
276 one URL shall be listed in each setting. If multiple resources need
277 to be referenced, it is recommended to provide an online landing
278 page linking all available resources.
279 Examples: "HOME_URL="https://fedoraproject.org/"",
281 "BUG_REPORT_URL="https://bugzilla.redhat.com/"".
282 SUPPORT_END=
284 The date at which support for this version of the OS ends. (What
285 exactly "lack of support" means varies between vendors, but
286 generally users should assume that updates, including security
287 fixes, will not be provided.) The value is a date in the ISO 8601
288 format "YYYY-MM-DD", and specifies the first day on which support
289 is not provided.
290 For example, "SUPPORT_END=2001-01-01" means that the system was
292 supported until the end of the last day of the previous millennium.
293 LOGO=
295 A string, specifying the name of an icon as defined by
296 freedesktop.org Icon Theme Specification[6]. This can be used by
297 graphical applications to display an operating system's or
298 distributor's logo. This field is optional and may not necessarily
299 be implemented on all systems.
300 Examples: "LOGO=fedora-logo", "LOGO=distributor-logo-opensuse"
302 ANSI_COLOR=
304 A suggested presentation color when showing the OS name on the
305 console. This should be specified as string suitable for inclusion
306 in the ESC [ m ANSI/ECMA-48 escape code for setting graphical
307 rendition. This field is optional.
308 Examples: "ANSI_COLOR="0;31"" for red, "ANSI_COLOR="1;34"" for
310 light blue, or "ANSI_COLOR="0;38;2;60;110;180"" for Fedora blue.
311 VENDOR_NAME=
313 The name of the OS vendor. This is the name of the organization or
314 company which produces the OS. This field is optional.
315 This name is intended to be exposed in "About this system" UIs or
317 software update UIs when needed to distinguish the OS vendor from
318 the OS itself. It is intended to be human readable.
319 Examples: "VENDOR_NAME="Fedora Project"" for Fedora Linux,
321 "VENDOR_NAME="Canonical"" for Ubuntu.
322 VENDOR_URL=
324 The homepage of the OS vendor. This field is optional. The
325 VENDOR_NAME= field should be set if this one is, although clients
326 must be robust against either field not being set.
327 The value should be in RFC3986 format[5], and should be "http:" or
329 "https:" URLs. Only one URL shall be listed in the setting.
330 Examples: "VENDOR_URL="https://fedoraproject.org/"",
332 "VENDOR_URL="https://canonical.com/"".
333 Distribution-level defaults and metadata
335 DEFAULT_HOSTNAME=
336 A string specifying the hostname if hostname(5) is not present and
337 no other configuration source specifies the hostname. Must be
338 either a single DNS label (a string composed of 7-bit ASCII
339 lower-case characters and no spaces or dots, limited to the format
340 allowed for DNS domain name labels), or a sequence of such labels
341 separated by single dots that forms a valid DNS FQDN. The hostname
342 must be at most 64 characters, which is a Linux limitation (DNS
343 allows longer names).
344 See org.freedesktop.hostname1(5) for a description of how systemd-
346 hostnamed.service(8) determines the fallback hostname.
347 ARCHITECTURE=
349 A string that specifies which CPU architecture the userspace
350 binaries require. The architecture identifiers are the same as for
351 ConditionArchitecture= described in systemd.unit(5). The field is
352 optional and should only be used when just single architecture is
353 supported. It may provide redundant information when used in a GPT
354 partition with a GUID type that already encodes the architecture.
355 If this is not the case, the architecture should be specified in
356 e.g., an extension image, to prevent an incompatible host from
357 loading it.
358 SYSEXT_LEVEL=
360 A lower-case string (mostly numeric, no spaces or other characters
361 outside of 0–9, a–z, ".", "_" and "-") identifying the operating
362 system extensions support level, to indicate which extension images
363 are supported. See
364 /usr/lib/extension-release.d/extension-release.IMAGE, initrd[2] and
365 systemd-sysext(8)) for more information.
366 Examples: "SYSEXT_LEVEL=2", "SYSEXT_LEVEL=15.14".
368 CONFEXT_LEVEL=
370 Semantically the same as SYSEXT_LEVEL= but for confext images. See
371 /etc/extension-release.d/extension-release.IMAGE for more
372 information.
373 Examples: "CONFEXT_LEVEL=2", "CONFEXT_LEVEL=15.14".
375 SYSEXT_SCOPE=
377 Takes a space-separated list of one or more of the strings
378 "system", "initrd" and "portable". This field is only supported in
379 extension-release.d/ files and indicates what environments the
380 system extension is applicable to: i.e. to regular systems, to
381 initrds, or to portable service images. If unspecified,
382 "SYSEXT_SCOPE=system portable" is implied, i.e. any system
383 extension without this field is applicable to regular systems and
384 to portable service environments, but not to initrd environments.
385 CONFEXT_SCOPE=
387 Semantically the same as SYSEXT_SCOPE= but for confext images.
388 PORTABLE_PREFIXES=
390 Takes a space-separated list of one or more valid prefix match
391 strings for the Portable Services Documentation[3] logic. This
392 field serves two purposes: it is informational, identifying
393 portable service images as such (and thus allowing them to be
394 distinguished from other OS images, such as bootable system
395 images). It is also used when a portable service image is attached:
396 the specified or implied portable service prefix is checked against
397 the list specified here, to enforce restrictions how images may be
398 attached to a system.
399 Notes
401 If you are using this file to determine the OS or a specific version of
402 it, use the ID and VERSION_ID fields, possibly with ID_LIKE as fallback
403 for ID. When looking for an OS identification string for presentation
404 to the user use the PRETTY_NAME field.
405 Note that operating system vendors may choose not to provide version
407 information, for example to accommodate for rolling releases. In this
408 case, VERSION and VERSION_ID may be unset. Applications should not rely
409 on these fields to be set.
410 Operating system vendors may extend the file format and introduce new
412 fields. It is highly recommended to prefix new fields with an OS
413 specific name in order to avoid name clashes. Applications reading this
414 file must ignore unknown fields.
415 Example: "DEBIAN_BTS="debbugs://bugs.debian.org/"".
417 Container and sandbox runtime managers may make the host's
419 identification data available to applications by providing the host's
420 /etc/os-release (if available, otherwise /usr/lib/os-release as a
421 fallback) as /run/host/os-release.
422
424 Example 1. os-release file for Fedora Workstation
425 NAME=Fedora
427 VERSION="32 (Workstation Edition)"
428 ID=fedora
429 VERSION_ID=32
430 PRETTY_NAME="Fedora 32 (Workstation Edition)"
431 ANSI_COLOR="0;38;2;60;110;180"
432 LOGO=fedora-logo-icon
433 CPE_NAME="cpe:/o:fedoraproject:fedora:32"
434 HOME_URL="https://fedoraproject.org/"
435 DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f32/system-administrators-guide/"
436 SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
437 BUG_REPORT_URL="https://bugzilla.redhat.com/"
438 REDHAT_BUGZILLA_PRODUCT="Fedora"
439 REDHAT_BUGZILLA_PRODUCT_VERSION=32
440 REDHAT_SUPPORT_PRODUCT="Fedora"
441 REDHAT_SUPPORT_PRODUCT_VERSION=32
442 PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
443 VARIANT="Workstation Edition"
444 VARIANT_ID=workstation
445 Example 2. extension-release file for an extension for Fedora
447 Workstation 32
448 ID=fedora
450 VERSION_ID=32
451 Example 3. Reading os-release in sh(1)
453 #!/bin/sh -eu
455 # SPDX-License-Identifier: MIT-0
456 test -e /etc/os-release && os_release='/etc/os-release' || os_release='/usr/lib/os-release'
458 . "${os_release}"
459 echo "Running on ${PRETTY_NAME:-Linux}"
461 if [ "${ID:-linux}" = "debian" ] || [ "${ID_LIKE#*debian*}" != "${ID_LIKE}" ]; then
463 echo "Looks like Debian!"
464 fi
465 Example 4. Reading os-release in python(1) (versions >= 3.10)
467 #!/usr/bin/python
469 # SPDX-License-Identifier: MIT-0
470 import platform
472 os_release = platform.freedesktop_os_release()
473 pretty_name = os_release.get('PRETTY_NAME', 'Linux')
475 print(f'Running on {pretty_name!r}')
476 if 'fedora' in [os_release.get('ID', 'linux'),
478 *os_release.get('ID_LIKE', '').split()]:
479 print('Looks like Fedora!')
480 See docs for platform.freedesktop_os_release[7] for more details.
482 Example 5. Reading os-release in python(1) (any version)
484 #!/usr/bin/python
486 # SPDX-License-Identifier: MIT-0
487 import ast
489 import re
490 import sys
491 def read_os_release():
493 try:
494 filename = '/etc/os-release'
495 f = open(filename)
496 except FileNotFoundError:
497 filename = '/usr/lib/os-release'
498 f = open(filename)
499 for line_number, line in enumerate(f, start=1):
501 line = line.rstrip()
502 if not line or line.startswith('#'):
503 continue
504 m = re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line)
505 if m:
506 name, val = m.groups()
507 if val and val[0] in '"\'':
508 val = ast.literal_eval(val)
509 yield name, val
510 else:
511 print(f'{filename}:{line_number}: bad line {line!r}',
512 file=sys.stderr)
513 os_release = dict(read_os_release())
515 pretty_name = os_release.get('PRETTY_NAME', 'Linux')
517 print(f'Running on {pretty_name!r}')
518 if 'debian' in [os_release.get('ID', 'linux'),
520 *os_release.get('ID_LIKE', '').split()]:
521 print('Looks like Debian!')
522 Note that the above version that uses the built-in implementation is
524 preferred in most cases, and the open-coded version here is provided
525 for reference.
526
528 systemd(1), lsb_release(1), hostname(5), machine-id(5), machine-info(5)
529
531 1. Announcement of /etc/os-release
532 https://0pointer.de/blog/projects/os-release
533 2. initrd
535 https://docs.kernel.org/admin-guide/initrd.html
536 3. Portable Services Documentation
538 https://systemd.io/PORTABLE_SERVICES
539 4. Common Platform Enumeration Specification
541 http://scap.nist.gov/specifications/cpe/
542 5. RFC3986 format
544 https://tools.ietf.org/html/rfc3986
545 6. freedesktop.org Icon Theme Specification
547 https://standards.freedesktop.org/icon-theme-spec/latest
548 7.
550 platform.freedesktop_os_release
552 https://docs.python.org/3/library/platform.html#platform.freedesktop_os_release
553systemd 254 OS-RELEASE(5)