1OS-RELEASE(5)                     os-release                     OS-RELEASE(5)
2
3
4

NAME

6       os-release, initrd-release, extension-release - Operating system
7       identification
8

SYNOPSIS

10       /etc/os-release
11
12       /usr/lib/os-release
13
14       /etc/initrd-release
15
16       /usr/lib/extension-release.d/extension-release.IMAGE
17

DESCRIPTION

19       The /etc/os-release and /usr/lib/os-release files contain operating
20       system identification data.
21
22       The basic file 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. It is not supported to concatenate multiple individually quoted
36       strings. Lines beginning with "#" shall be ignored as comments. Blank
37       lines are permitted and ignored.
38
39       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
50       os-release contains data that is defined by the operating system vendor
51       and should generally not be changed by the administrator.
52
53       As this file only encodes names and identifiers it should not be
54       localized.
55
56       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
60       For a longer rationale for os-release please refer to the Announcement
61       of /etc/os-release[1].
62
63   /etc/initrd-release
64       In the initrd[2], /etc/initrd-release plays the same role as os-release
65       in the main system. Additionally, the presence of that file means that
66       the system is in the initrd phase.  /etc/os-release should be symlinked
67       to /etc/initrd-release (or vice versa), so programs that only look for
68       /etc/os-release (as described above) work correctly.
69
70       The rest of this document that talks about os-release should be
71       understood to apply to initrd-release too.
72
73   /usr/lib/extension-release.d/extension-release.IMAGE
74       /usr/lib/extension-release.d/extension-release.IMAGE plays the same
75       role for extension images as os-release for the main system, and
76       follows the syntax and rules as described in the Portable Services
77       Documentation[3]. The purpose of this file is to identify the extension
78       and to allow the operating system to verify that the extension image
79       matches the base OS. This is typically implemented by checking that the
80       ID= options match, and either SYSEXT_LEVEL= exists and matches too, or
81       if it is not present, VERSION_ID= exists and matches. This ensures
82       ABI/API compatibility between the layers and prevents merging of an
83       incompatible image in an overlay.
84
85       In the extension-release.IMAGE filename, the IMAGE part must exactly
86       match the file name of the containing image with the suffix removed. In
87       case it is not possible to guarantee that an image file name is stable
88       and doesn't change between the build and the deployment phases, it is
89       possible to relax this check: if exactly one file whose name matches
90       "extension-release.*"  is present in this directory, and the file is
91       tagged with a user.extension-release.strict xattr(7) set to the string
92       "0", it will be used instead.
93
94       The rest of this document that talks about os-release should be
95       understood to apply to extension-release too.
96

OPTIONS

98       The following OS identifications parameters may be set using
99       os-release:
100
101   General information identifying the operating system
102       NAME=
103           A string identifying the operating system, without a version
104           component, and suitable for presentation to the user. If not set, a
105           default of "NAME=Linux" may be used.
106
107           Examples: "NAME=Fedora", "NAME="Debian GNU/Linux"".
108
109       ID=
110           A lower-case string (no spaces or other characters outside of 0–9,
111           a–z, ".", "_" and "-") identifying the operating system, excluding
112           any version information and suitable for processing by scripts or
113           usage in generated filenames. If not set, a default of "ID=linux"
114           may be used. Note that even though this string may not include
115           characters that require shell quoting, quoting may nevertheless be
116           used.
117
118           Examples: "ID=fedora", "ID=debian".
119
120       ID_LIKE=
121           A space-separated list of operating system identifiers in the same
122           syntax as the ID= setting. It should list identifiers of operating
123           systems that are closely related to the local operating system in
124           regards to packaging and programming interfaces, for example
125           listing one or more OS identifiers the local OS is a derivative
126           from. An OS should generally only list other OS identifiers it
127           itself is a derivative of, and not any OSes that are derived from
128           it, though symmetric relationships are possible. Build scripts and
129           similar should check this variable if they need to identify the
130           local operating system and the value of ID= is not recognized.
131           Operating systems should be listed in order of how closely the
132           local operating system relates to the listed ones, starting with
133           the closest. This field is optional.
134
135           Examples: for an operating system with "ID=centos", an assignment
136           of "ID_LIKE="rhel fedora"" would be appropriate. For an operating
137           system with "ID=ubuntu", an assignment of "ID_LIKE=debian" is
138           appropriate.
139
140       PRETTY_NAME=
141           A pretty operating system name in a format suitable for
142           presentation to the user. May or may not contain a release code
143           name or OS version of some kind, as suitable. If not set, a default
144           of "PRETTY_NAME="Linux"" may be used
145
146           Example: "PRETTY_NAME="Fedora 17 (Beefy Miracle)"".
147
148       CPE_NAME=
149           A CPE name for the operating system, in URI binding syntax,
150           following the Common Platform Enumeration Specification[4] as
151           proposed by the NIST. This field is optional.
152
153           Example: "CPE_NAME="cpe:/o:fedoraproject:fedora:17""
154
155       VARIANT=
156           A string identifying a specific variant or edition of the operating
157           system suitable for presentation to the user. This field may be
158           used to inform the user that the configuration of this system is
159           subject to a specific divergent set of rules or default
160           configuration settings. This field is optional and may not be
161           implemented on all systems.
162
163           Examples: "VARIANT="Server Edition"", "VARIANT="Smart Refrigerator
164           Edition"".
165
166           Note: this field is for display purposes only. The VARIANT_ID field
167           should be used for making programmatic decisions.
168
169       VARIANT_ID=
170           A lower-case string (no spaces or other characters outside of 0–9,
171           a–z, ".", "_" and "-"), identifying a specific variant or edition
172           of the operating system. This may be interpreted by other packages
173           in order to determine a divergent default configuration. This field
174           is optional and may not be implemented on all systems.
175
176           Examples: "VARIANT_ID=server", "VARIANT_ID=embedded".
177
178   Information about the version of the operating system
179       VERSION=
180           A string identifying the operating system version, excluding any OS
181           name information, possibly including a release code name, and
182           suitable for presentation to the user. This field is optional.
183
184           Examples: "VERSION=17", "VERSION="17 (Beefy Miracle)"".
185
186       VERSION_ID=
187           A lower-case string (mostly numeric, no spaces or other characters
188           outside of 0–9, a–z, ".", "_" and "-") identifying the operating
189           system version, excluding any OS name information or release code
190           name, and suitable for processing by scripts or usage in generated
191           filenames. This field is optional.
192
193           Examples: "VERSION_ID=17", "VERSION_ID=11.04".
194
195       VERSION_CODENAME=
196           A lower-case string (no spaces or other characters outside of 0–9,
197           a–z, ".", "_" and "-") identifying the operating system release
198           code name, excluding any OS name information or release version,
199           and suitable for processing by scripts or usage in generated
200           filenames. This field is optional and may not be implemented on all
201           systems.
202
203           Examples: "VERSION_CODENAME=buster", "VERSION_CODENAME=xenial".
204
205       BUILD_ID=
206           A string uniquely identifying the system image originally used as
207           the installation base. In most cases, VERSION_ID or
208           IMAGE_ID+IMAGE_VERSION are updated when the entire system image is
209           replaced during an update.  BUILD_ID may be used in distributions
210           where the original installation image version is important:
211           VERSION_ID would change during incremental system updates, but
212           BUILD_ID would not. This field is optional.
213
214           Examples: "BUILD_ID="2013-03-20.3"", "BUILD_ID=201303203".
215
216       IMAGE_ID=
217           A lower-case string (no spaces or other characters outside of 0–9,
218           a–z, ".", "_" and "-"), identifying a specific image of the
219           operating system. This is supposed to be used for environments
220           where OS images are prepared, built, shipped and updated as
221           comprehensive, consistent OS images. This field is optional and may
222           not be implemented on all systems, in particularly not on those
223           that are not managed via images but put together and updated from
224           individual packages and on the local system.
225
226           Examples: "IMAGE_ID=vendorx-cashier-system",
227           "IMAGE_ID=netbook-image".
228
229       IMAGE_VERSION=
230           A lower-case string (mostly numeric, no spaces or other characters
231           outside of 0–9, a–z, ".", "_" and "-") identifying the OS image
232           version. This is supposed to be used together with IMAGE_ID
233           described above, to discern different versions of the same image.
234
235           Examples: "IMAGE_VERSION=33", "IMAGE_VERSION=47.1rc1".
236
237       To summarize: if the image updates are built and shipped as
238       comprehensive units, IMAGE_ID+IMAGE_VERSION is the best fit. Otherwise,
239       if updates eventually completely replace previously installed contents,
240       as in a typical binary distribution, VERSION_ID should be used to
241       identify major releases of the operating system.  BUILD_ID may be used
242       instead or in addition to VERSION_ID when the original system image
243       version is important.
244
245   Presentation information and links
246       HOME_URL=, DOCUMENTATION_URL=, SUPPORT_URL=, BUG_REPORT_URL=,
247       PRIVACY_POLICY_URL=
248           Links to resources on the Internet related to the operating system.
249           HOME_URL= should refer to the homepage of the operating system, or
250           alternatively some homepage of the specific version of the
251           operating system.  DOCUMENTATION_URL= should refer to the main
252           documentation page for this operating system.  SUPPORT_URL= should
253           refer to the main support page for the operating system, if there
254           is any. This is primarily intended for operating systems which
255           vendors provide support for.  BUG_REPORT_URL= should refer to the
256           main bug reporting page for the operating system, if there is any.
257           This is primarily intended for operating systems that rely on
258           community QA.  PRIVACY_POLICY_URL= should refer to the main privacy
259           policy page for the operating system, if there is any. These
260           settings are optional, and providing only some of these settings is
261           common. These URLs are intended to be exposed in "About this
262           system" UIs behind links with captions such as "About this
263           Operating System", "Obtain Support", "Report a Bug", or "Privacy
264           Policy". The values should be in RFC3986 format[5], and should be
265           "http:" or "https:" URLs, and possibly "mailto:" or "tel:". Only
266           one URL shall be listed in each setting. If multiple resources need
267           to be referenced, it is recommended to provide an online landing
268           page linking all available resources.
269
270           Examples: "HOME_URL="https://fedoraproject.org/"",
271           "BUG_REPORT_URL="https://bugzilla.redhat.com/"".
272
273       LOGO=
274           A string, specifying the name of an icon as defined by
275           freedesktop.org Icon Theme Specification[6]. This can be used by
276           graphical applications to display an operating system's or
277           distributor's logo. This field is optional and may not necessarily
278           be implemented on all systems.
279
280           Examples: "LOGO=fedora-logo", "LOGO=distributor-logo-opensuse"
281
282       ANSI_COLOR=
283           A suggested presentation color when showing the OS name on the
284           console. This should be specified as string suitable for inclusion
285           in the ESC [ m ANSI/ECMA-48 escape code for setting graphical
286           rendition. This field is optional.
287
288           Examples: "ANSI_COLOR="0;31"" for red, "ANSI_COLOR="1;34"" for
289           light blue, or "ANSI_COLOR="0;38;2;60;110;180"" for Fedora blue.
290
291   Distribution-level defaults and metadata
292       DEFAULT_HOSTNAME=
293           A string specifying the hostname if hostname(5) is not present and
294           no other configuration source specifies the hostname. Must be
295           either a single DNS label (a string composed of 7-bit ASCII
296           lower-case characters and no spaces or dots, limited to the format
297           allowed for DNS domain name labels), or a sequence of such labels
298           separated by single dots that forms a valid DNS FQDN. The hostname
299           must be at most 64 characters, which is a Linux limitation (DNS
300           allows longer names).
301
302           See org.freedesktop.hostname1(5) for a description of how systemd-
303           hostnamed.service(8) determines the fallback hostname.
304
305       SYSEXT_LEVEL=
306           A lower-case string (mostly numeric, no spaces or other characters
307           outside of 0–9, a–z, ".", "_" and "-") identifying the operating
308           system extensions support level, to indicate which extension images
309           are supported. See
310           /usr/lib/extension-release.d/extension-release.IMAGE, initrd[2] and
311           systemd-sysext(8)) for more information.
312
313           Examples: "SYSEXT_LEVEL=2", "SYSEXT_LEVEL=15.14".
314
315       SYSEXT_SCOPE=
316           Takes a space-separated list of one or more of the strings
317           "system", "initrd" and "portable". This field is only supported in
318           extension-release.d/ files and indicates what environments the
319           system extension is applicable to: i.e. to regular systems, to
320           initial RAM filesystems ("initrd") or to portable service images.
321           If unspecified, "SYSEXT_SCOPE=system portable" is implied, i.e. any
322           system extension without this field is applicable to regular
323           systems and to portable service environments, but not to initrd
324           environments.
325
326       PORTABLE_PREFIXES=
327           Takes a space-separated list of one or more valid prefix match
328           strings for the Portable Services[3] logic. This field serves two
329           purposes: it is informational, identifying portable service images
330           as such (and thus allowing them to be distinguished from other OS
331           images, such as bootable system images). In is also used when a
332           portable service image is attached: the specified or implied
333           portable service prefix is checked against the list specified here,
334           to enforce restrictions how images may be attached to a system.
335
336   Notes
337       If you are using this file to determine the OS or a specific version of
338       it, use the ID and VERSION_ID fields, possibly with ID_LIKE as fallback
339       for ID. When looking for an OS identification string for presentation
340       to the user use the PRETTY_NAME field.
341
342       Note that operating system vendors may choose not to provide version
343       information, for example to accommodate for rolling releases. In this
344       case, VERSION and VERSION_ID may be unset. Applications should not rely
345       on these fields to be set.
346
347       Operating system vendors may extend the file format and introduce new
348       fields. It is highly recommended to prefix new fields with an OS
349       specific name in order to avoid name clashes. Applications reading this
350       file must ignore unknown fields.
351
352       Example: "DEBIAN_BTS="debbugs://bugs.debian.org/"".
353
354       Container and sandbox runtime managers may make the host's
355       identification data available to applications by providing the host's
356       /etc/os-release (if available, otherwise /usr/lib/os-release as a
357       fallback) as /run/host/os-release.
358

EXAMPLES

360       Example 1. os-release file for Fedora Workstation
361
362           NAME=Fedora
363           VERSION="32 (Workstation Edition)"
364           ID=fedora
365           VERSION_ID=32
366           PRETTY_NAME="Fedora 32 (Workstation Edition)"
367           ANSI_COLOR="0;38;2;60;110;180"
368           LOGO=fedora-logo-icon
369           CPE_NAME="cpe:/o:fedoraproject:fedora:32"
370           HOME_URL="https://fedoraproject.org/"
371           DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f32/system-administrators-guide/"
372           SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
373           BUG_REPORT_URL="https://bugzilla.redhat.com/"
374           REDHAT_BUGZILLA_PRODUCT="Fedora"
375           REDHAT_BUGZILLA_PRODUCT_VERSION=32
376           REDHAT_SUPPORT_PRODUCT="Fedora"
377           REDHAT_SUPPORT_PRODUCT_VERSION=32
378           PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
379           VARIANT="Workstation Edition"
380           VARIANT_ID=workstation
381
382       Example 2. extension-release file for an extension for Fedora
383       Workstation 32
384
385           ID=fedora
386           VERSION_ID=32
387
388       Example 3. Reading os-release in sh(1)
389
390           #!/bin/sh -eu
391           # SPDX-License-Identifier: CC0-1.0
392
393           test -e /etc/os-release && os_release='/etc/os-release' || os_release='/usr/lib/os-release'
394           . "${os_release}"
395
396           echo "Running on ${PRETTY_NAME:-Linux}"
397
398           if [ "${ID:-linux}" = "debian" ] || [ "${ID_LIKE#*debian*}" != "${ID_LIKE}" ]; then
399               echo "Looks like Debian!"
400           fi
401
402       Example 4. Reading os-release in python(1) (versions >= 3.10)
403
404           #!/usr/bin/python
405           # SPDX-License-Identifier: CC0-1.0
406
407           import platform
408           os_release = platform.freedesktop_os_release()
409
410           pretty_name = os_release.get('PRETTY_NAME', 'Linux')
411           print(f'Running on {pretty_name!r}')
412
413           if 'fedora' in [os_release.get('ID', 'linux'),
414                           *os_release.get('ID_LIKE', '').split()]:
415               print('Looks like Fedora!')
416
417       See docs for platform.freedesktop_os_release[7] for more details.
418
419       Example 5. Reading os-release in python(1) (any version)
420
421           #!/usr/bin/python
422           # SPDX-License-Identifier: CC0-1.0
423
424           import ast
425           import re
426           import sys
427
428           def read_os_release():
429               try:
430                   filename = '/etc/os-release'
431                   f = open(filename)
432               except FileNotFoundError:
433                   filename = '/usr/lib/os-release'
434                   f = open(filename)
435
436               for line_number, line in enumerate(f, start=1):
437                   line = line.rstrip()
438                   if not line or line.startswith('#'):
439                       continue
440                   if m := re.match(r'([A-Z][A-Z_0-9]+)=(.*)', line):
441                       name, val = m.groups()
442                       if val and val[0] in '"\'':
443                           val = ast.literal_eval(val)
444                       yield name, val
445                   else:
446                       print(f'{filename}:{line_number}: bad line {line!r}',
447                             file=sys.stderr)
448
449           os_release = dict(read_os_release())
450
451           pretty_name = os_release.get('PRETTY_NAME', 'Linux')
452           print(f'Running on {pretty_name!r}')
453
454           if 'debian' in [os_release.get('ID', 'linux'),
455                           *os_release.get('ID_LIKE', '').split()]:
456               print('Looks like Debian!')
457
458       Note that the above version that uses the built-in implementation is
459       preferred in most cases, and the open-coded version here is provided
460       for reference.
461

SEE ALSO

463       systemd(1), lsb_release(1), hostname(5), machine-id(5), machine-info(5)
464

NOTES

466        1. Announcement of /etc/os-release
467           http://0pointer.de/blog/projects/os-release
468
469        2. initrd
470           https://www.kernel.org/doc/html/latest/admin-guide/initrd.html
471
472        3. Portable Services Documentation
473           https://systemd.io/PORTABLE_SERVICES
474
475        4. Common Platform Enumeration Specification
476           http://scap.nist.gov/specifications/cpe/
477
478        5. RFC3986 format
479           https://tools.ietf.org/html/rfc3986
480
481        6. freedesktop.org Icon Theme Specification
482           http://standards.freedesktop.org/icon-theme-spec/latest
483
484        7.
485
486                 platform.freedesktop_os_release
487           https://docs.python.org/3/library/platform.html#platform.freedesktop_os_release
488
489
490
491systemd 250                                                      OS-RELEASE(5)
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