1SOURCES.LIST(5) APT SOURCES.LIST(5)
2
6 sources.list - List of configured APT data sources
7
9 The source list /etc/apt/sources.list and the files contained in
10 /etc/apt/sources.list.d/ are designed to support any number of active
11 sources and a variety of source media. The files list one source per
12 line (one-line style) or contain multiline stanzas defining one or more
13 sources per stanza (deb822 style), with the most preferred source
14 listed first (in case a single version is available from more than one
15 source). The information available from the configured sources is
16 acquired by apt-get update (or by an equivalent command from another
17 APT front-end).
18
20 The /etc/apt/sources.list.d directory provides a way to add
21 sources.list entries in separate files. Two different file formats are
22 allowed as described in the next two sections. Filenames need to have
23 either the extension .list or .sources depending on the contained
24 format. The filenames may only contain letters (a-z and A-Z), digits
25 (0-9), underscore (_), hyphen (-) and period (.) characters. Otherwise
26 APT will print a notice that it has ignored a file, unless that file
27 matches a pattern in the Dir::Ignore-Files-Silently configuration list
28 - in which case it will be silently ignored.
29
31 Files in this format have the extension .list. Each line specifying a
32 source starts with a type (e.g. deb-src) followed by options and
33 arguments for this type. Individual entries cannot be continued onto a
34 following line. Empty lines are ignored, and a # character anywhere on
35 a line marks the remainder of that line as a comment. Consequently an
36 entry can be disabled by commenting out the entire line. If options
37 should be provided they are separated by spaces and all of them
38 together are enclosed by square brackets ([]) included in the line
39 after the type separated from it with a space. If an option allows
40 multiple values these are separated from each other with a comma (,).
41 An option name is separated from its value(s) by an equals sign (=).
42 Multivalue options also have -= and += as separators, which instead of
43 replacing the default with the given value(s) modify the default
44 value(s) to remove or include the given values.
45 This is the traditional format and supported by all apt versions. Note
47 that not all options as described below are supported by all apt
48 versions. Note also that some older applications parsing this format on
49 their own might not expect to encounter options as they were uncommon
50 before the introduction of multi-architecture support.
51
53 Files in this format have the extension .sources. The format is similar
54 in syntax to other files used by Debian and its derivatives, such as
55 the metadata files that apt will download from the configured sources
56 or the debian/control file in a Debian source package. Individual
57 entries are separated by an empty line; additional empty lines are
58 ignored, and a # character at the start of the line marks the entire
59 line as a comment. An entry can hence be disabled by commenting out
60 each line belonging to the stanza, but it is usually easier to add the
61 field "Enabled: no" to the stanza to disable the entry. Removing the
62 field or setting it to yes re-enables it. Options have the same syntax
63 as every other field: A field name separated by a colon (:) and
64 optionally spaces from its value(s). Note especially that multiple
65 values are separated by whitespaces (like spaces, tabs and newlines),
66 not by commas as in the one-line format. Multivalue fields like
67 Architectures also have Architectures-Add and Architectures-Remove to
68 modify the default value rather than replacing it.
69 This is a new format supported by apt itself since version 1.1.
71 Previous versions ignore such files with a notice message as described
72 earlier. It is intended to make this format gradually the default
73 format, deprecating the previously described one-line-style format, as
74 it is easier to create, extend and modify for humans and machines alike
75 especially if a lot of sources and/or options are involved. Developers
76 who are working with and/or parsing apt sources are highly encouraged
77 to add support for this format and to contact the APT team to
78 coordinate and share this work. Users can freely adopt this format
79 already, but may encounter problems with software not supporting the
80 format yet.
81
83 The deb type references a typical two-level Debian archive,
84 distribution/component. The distribution is generally a suite name like
85 stable or testing or a codename like bullseye or bookworm while
86 component is one of main, contrib or non-free. The deb-src type
87 references a Debian distribution's source code in the same form as the
88 deb type. A deb-src line is required to fetch source indexes.
89 The format for two one-line-style entries using the deb and deb-src
91 types is:
92 deb [ option1=value1 option2=value2 ] uri suite [component1] [component2] [...]
94 deb-src [ option1=value1 option2=value2 ] uri suite [component1] [component2] [...]
95 Alternatively the equivalent entry in deb822 style looks like this:
97 Types: deb deb-src
99 URIs: uri
100 Suites: suite
101 Components: [component1] [component2] [...]
102 option1: value1
103 option2: value2
104 The URI for the deb type must specify the base of the Debian
107 distribution, from which APT will find the information it needs. suite
108 can specify an exact path, in which case the components must be omitted
109 and suite must end with a slash (/). This is useful for the case when
110 only a particular sub-directory of the archive denoted by the URI is of
111 interest. If suite does not specify an exact path, at least one
112 component must be present.
113 suite may also contain a variable, $(ARCH) which expands to the Debian
115 architecture (such as amd64 or armel) used on the system. This permits
116 architecture-independent sources.list files to be used. In general this
117 is only of interest when specifying an exact path; APT will
118 automatically generate a URI with the current architecture otherwise.
119 Especially in the one-line-style format since only one distribution can
121 be specified per line it may be necessary to have multiple lines for
122 the same URI, if a subset of all available distributions or components
123 at that location is desired. APT will sort the URI list after it has
124 generated a complete set internally, and will collapse multiple
125 references to the same Internet host, for instance, into a single
126 connection, so that it does not inefficiently establish a connection,
127 close it, do something else, and then re-establish a connection to that
128 same host. APT also parallelizes connections to different hosts to more
129 effectively deal with sites with low bandwidth.
130 It is important to list sources in order of preference, with the most
132 preferred source listed first. Typically this will result in sorting by
133 speed from fastest to slowest (CD-ROM followed by hosts on a local
134 network, followed by distant Internet hosts, for example).
135 As an example, the sources for your distribution could look like this
137 in one-line-style format:
138 deb http://deb.debian.org/debian bullseye main contrib non-free
140 deb http://security.debian.org bullseye-security main contrib non-free
141 or like this in deb822 style format:
143 Types: deb
145 URIs: http://deb.debian.org/debian
146 Suites: bullseye
147 Components: main contrib non-free
148 Types: deb
150 URIs: http://security.debian.org
151 Suites: bullseye-security
152 Components: main contrib non-free
153
155 Each source entry can have options specified to modify which source is
156 accessed and how data is acquired from it. Format, syntax and names of
157 the options vary between the one-line-style and deb822-style formats as
158 described, but they both have the same options available. For
159 simplicity we list the deb822 field name and provide the one-line name
160 in brackets. Remember that besides setting multivalue options
161 explicitly, there is also the option to modify them based on the
162 default, but we aren't listing those names explicitly here. Unsupported
163 options are silently ignored by all APT versions.
164 • Architectures (arch) is a multivalue option defining for which
166 architectures information should be downloaded. If this option
167 isn't set the default is all architectures as defined by the
168 APT::Architectures config option.
169 • Languages (lang) is a multivalue option defining for which
171 languages information such as translated package descriptions
172 should be downloaded. If this option isn't set the default is all
173 languages as defined by the Acquire::Languages config option.
174 • Targets (target) is a multivalue option defining which download
176 targets apt will try to acquire from this source. If not specified,
177 the default set is defined by the Acquire::IndexTargets
178 configuration scope (targets are specified by their name in the
179 Created-By field). Additionally, targets can be enabled or disabled
180 by using the Identifier field as an option with a boolean value
181 instead of using this multivalue option.
182 • PDiffs (pdiffs) is a yes/no value which controls if APT should try
184 to use PDiffs to update old indexes instead of downloading the new
185 indexes entirely. The value of this option is ignored if the
186 repository doesn't announce the availability of PDiffs. Defaults to
187 the value of the option with the same name for a specific index
188 file defined in the Acquire::IndexTargets scope, which itself
189 defaults to the value of configuration option Acquire::PDiffs which
190 defaults to yes.
191 • By-Hash (by-hash) can have the value yes, no or force and controls
193 if APT should try to acquire indexes via a URI constructed from a
194 hashsum of the expected file instead of using the well-known stable
195 filename of the index. Using this can avoid hashsum mismatches, but
196 requires a supporting mirror. A yes or no value activates/disables
197 the use of this feature if this source indicates support for it,
198 while force will enable the feature regardless of what the source
199 indicates. Defaults to the value of the option of the same name for
200 a specific index file defined in the Acquire::IndexTargets scope,
201 which itself defaults to the value of configuration option
202 Acquire::By-Hash which defaults to yes.
203 Furthermore, there are options which if set affect all sources with the
205 same URI and Suite, so they have to be set on all such entries and can
206 not be varied between different components. APT will try to detect and
207 error out on such anomalies.
208 • Allow-Insecure (allow-insecure), Allow-Weak (allow-weak) and
210 Allow-Downgrade-To-Insecure (allow-downgrade-to-insecure) are
211 boolean values which all default to no. If set to yes they
212 circumvent parts of apt-secure(8) and should therefore not be used
213 lightly!
214 • Trusted (trusted) is a tri-state value which defaults to APT
216 deciding if a source is considered trusted or if warnings should be
217 raised before e.g. packages are installed from this source. This
218 option can be used to override that decision. The value yes tells
219 APT always to consider this source as trusted, even if it doesn't
220 pass authentication checks. It disables parts of apt-secure(8), and
221 should therefore only be used in a local and trusted context (if at
222 all) as otherwise security is breached. The value no does the
223 opposite, causing the source to be handled as untrusted even if the
224 authentication checks passed successfully. The default value can't
225 be set explicitly.
226 • Signed-By (signed-by) is an option to require a repository to pass
228 apt-secure(8) verification with a certain set of keys rather than
229 all trusted keys apt has configured. It is specified as a list of
230 absolute paths to keyring files (have to be accessible and readable
231 for the _apt system user, so ensure everyone has read-permissions
232 on the file) and fingerprints of keys to select from these
233 keyrings. If no keyring files are specified the default is the
234 trusted.gpg keyring and all keyrings in the trusted.gpg.d/
235 directory (see apt-key fingerprint). If no fingerprint is specified
236 all keys in the keyrings are selected. A fingerprint will accept
237 also all signatures by a subkey of this key, if this isn't desired
238 an exclamation mark (!) can be appended to the fingerprint to
239 disable this behaviour. The option defaults to the value of the
240 option with the same name if set in the previously acquired Release
241 file of this repository (only fingerprints can be specified there
242 through). Otherwise all keys in the trusted keyrings are considered
243 valid signers for this repository. The option may also be set
244 directly to an embedded GPG public key block. Special care is
245 needed to encode the empty line with leading spaces and ".":
246 Types: deb
248 URIs: https://deb.debian.org
249 Suites: stable
250 Components: main contrib non-free
251 Signed-By:
252 -----BEGIN PGP PUBLIC KEY BLOCK-----
253 .
254 mDMEYCQjIxYJKwYBBAHaRw8BAQdAD/P5Nvvnvk66SxBBHDbhRml9ORg1WV5CvzKY
255 CuMfoIS0BmFiY2RlZoiQBBMWCgA4FiEErCIG1VhKWMWo2yfAREZd5NfO31cFAmAk
256 IyMCGyMFCwkIBwMFFQoJCAsFFgIDAQACHgECF4AACgkQREZd5NfO31fbOwD6ArzS
257 dM0Dkd5h2Ujy1b6KcAaVW9FOa5UNfJ9FFBtjLQEBAJ7UyWD3dZzhvlaAwunsk7DG
258 3bHcln8DMpIJVXht78sL
259 =IE0r
260 -----END PGP PUBLIC KEY BLOCK-----
261 • Check-Valid-Until (check-valid-until) is a yes/no value which
264 controls if APT should try to detect replay attacks. A repository
265 creator can declare a time until which the data provided in the
266 repository should be considered valid, and if this time is reached,
267 but no new data is provided, the data is considered expired and an
268 error is raised. Besides increasing security, as a malicious
269 attacker can't send old data forever to prevent a user from
270 upgrading to a new version, this also helps users identify mirrors
271 which are no longer updated. However, some repositories such as
272 historic archives are not updated any more by design, so this check
273 can be disabled by setting this option to no. Defaults to the value
274 of configuration option Acquire::Check-Valid-Until which itself
275 defaults to yes.
276 • Valid-Until-Min (valid-until-min) and Valid-Until-Max
278 (valid-until-max) can be used to raise or lower the time period in
279 seconds in which the data from this repository is considered valid.
280 -Max can be especially useful if the repository provides no
281 Valid-Until field on its Release file to set your own value, while
282 -Min can be used to increase the valid time on seldom updated
283 (local) mirrors of a more frequently updated but less accessible
284 archive (which is in the sources.list as well) instead of disabling
285 the check entirely. Default to the value of the configuration
286 options Acquire::Min-ValidTime and Acquire::Max-ValidTime which are
287 both unset by default.
288 • Check-Date (check-date) is a yes/no value which controls if APT
290 should consider the machine's time correct and hence perform time
291 related checks, such as verifying that a Release file is not from
292 the future. Disabling it also disables the Check-Valid-Until option
293 mentioned above.
294 • Date-Max-Future (date-max-future) controls how far from the future
296 a repository may be. Default to the value of the configuration
297 option Acquire::Max-FutureTime which is 10 seconds by default.
298 • InRelease-Path (inrelease-path) determines the path to the
300 InRelease file, relative to the normal position of an InRelease
301 file. By default, this option is unset and APT will try to fetch an
302 InRelease or, if that fails, a Release file and its associated
303 Release.gpg file. By setting this option, the specified path will
304 be tried instead of the InRelease file, and the fallback to Release
305 files will be disabled.
306
309 The currently recognized URI types are:
310 http (apt-transport-http(1))
312 The http scheme specifies an HTTP server for an archive and is the
313 most commonly used method. The URI can directly include login
314 information if the archive requires it, but the use of
315 apt_auth.conf(5) should be preferred. The method also supports
316 SOCKS5 and HTTP(S) proxies either configured via apt-specific
317 configuration or specified by the environment variable http_proxy
318 in the format (assuming an HTTP proxy requiring authentication)
319 http://user:pass@server:port/. The authentication details for
320 proxies can also be supplied via apt_auth.conf(5).
321 Note that these forms of authentication are insecure as the whole
323 communication with the remote server (or proxy) is not encrypted so
324 a sufficiently capable attacker can observe and record login as
325 well as all other interactions. The attacker can not modify the
326 communication through as APT's data security model is independent
327 of the chosen transport method. See apt-secure(8) for details.
328 https (apt-transport-https(1))
330 The https scheme specifies an HTTPS server for an archive and is
331 very similar in use and available options to the http scheme. The
332 main difference is that the communication between apt and server
333 (or proxy) is encrypted. Note that the encryption does not prevent
334 an attacker from knowing which server (or proxy) apt is
335 communicating with and deeper analysis can potentially still reveal
336 which data was downloaded. If this is a concern the Tor-based
337 schemes mentioned further below might be a suitable alternative.
338 mirror, mirror+scheme (apt-transport-mirror(1))
340 The mirror scheme specifies the location of a mirrorlist. By
341 default the scheme used for the location is http, but any other
342 scheme can be used via mirror+scheme. The mirrorlist itself can
343 contain many different URIs for mirrors the APT client can
344 transparently pick, choose and fallback between intended to help
345 both with distributing the load over the available mirrors and
346 ensuring that clients can acquire data even if some configured
347 mirrors are not available.
348 file
350 The file scheme allows an arbitrary directory in the file system to
351 be considered an archive. This is useful for NFS mounts and local
352 mirrors or archives.
353 cdrom
355 The cdrom scheme allows APT to use a local CD-ROM, DVD or USB drive
356 with media swapping. Use the apt-cdrom(8) program to create cdrom
357 entries in the source list.
358 ftp
360 The ftp scheme specifies an FTP server for an archive. Use of FTP
361 is on the decline in favour of http and https and many archives
362 either never offered or are retiring FTP access. If you still need
363 this method many configuration options for it are available in the
364 Acquire::ftp scope and detailed in apt.conf(5).
365 Please note that an FTP proxy can be specified by using the
367 ftp_proxy environment variable. It is possible to specify an HTTP
368 proxy (HTTP proxy servers often understand FTP URLs) using this
369 environment variable and only this environment variable. Proxies
370 using HTTP specified in the configuration file will be ignored.
371 copy
373 The copy scheme is identical to the file scheme except that
374 packages are copied into the cache directory instead of used
375 directly at their location. This is useful for people using
376 removable media to copy files around with APT.
377 rsh, ssh
379 The rsh/ssh method invokes RSH/SSH to connect to a remote host and
380 access the files as a given user. Prior configuration of rhosts or
381 RSA keys is recommended. The standard find and dd commands are used
382 to perform the file transfers from the remote host.
383 adding more recognizable URI types
385 APT can be extended with more methods shipped in other optional
386 packages, which should follow the naming scheme
387 apt-transport-method. For instance, the APT team also maintains the
388 package apt-transport-tor, which provides access methods for HTTP
389 and HTTPS URIs routed via the Tor network.
390
392 Uses the archive stored locally (or NFS mounted) at /home/apt/debian
393 for stable/main, stable/contrib, and stable/non-free.
394 deb file:/home/apt/debian stable main contrib non-free
396 Types: deb
398 URIs: file:/home/apt/debian
399 Suites: stable
400 Components: main contrib non-free
401 As above, except this uses the unstable (development) distribution.
403 deb file:/home/apt/debian unstable main contrib non-free
405 Types: deb
407 URIs: file:/home/apt/debian
408 Suites: unstable
409 Components: main contrib non-free
410 Sources specification for the above.
412 deb-src file:/home/apt/debian unstable main contrib non-free
414 Types: deb-src
416 URIs: file:/home/apt/debian
417 Suites: unstable
418 Components: main contrib non-free
419 The first line gets package information for the architectures in
421 APT::Architectures while the second always retrieves amd64 and armel.
422 deb http://deb.debian.org/debian bullseye main
424 deb [ arch=amd64,armel ] http://deb.debian.org/debian bullseye main
425 Types: deb
427 URIs: http://deb.debian.org/debian
428 Suites: bullseye
429 Components: main
430 Types: deb
432 URIs: http://deb.debian.org/debian
433 Suites: bullseye
434 Components: main
435 Architectures: amd64 armel
436 Uses HTTP to access the archive at archive.debian.org, and uses only
438 the hamm/main area.
439 deb http://archive.debian.org/debian-archive hamm main
441 Types: deb
443 URIs: http://archive.debian.org/debian-archive
444 Suites: hamm
445 Components: main
446 Uses FTP to access the archive at ftp.debian.org, under the debian
448 directory, and uses only the bullseye/contrib area.
449 deb ftp://ftp.debian.org/debian bullseye contrib
451 Types: deb
453 URIs: ftp://ftp.debian.org/debian
454 Suites: bullseye
455 Components: contrib
456 Uses FTP to access the archive at ftp.debian.org, under the debian
458 directory, and uses only the unstable/contrib area. If this line
459 appears as well as the one in the previous example in sources.list a
460 single FTP session will be used for both resource lines.
461 deb ftp://ftp.debian.org/debian unstable contrib
463 Types: deb
465 URIs: ftp://ftp.debian.org/debian
466 Suites: unstable
467 Components: contrib
468 Uses HTTP to access the archive at ftp.tlh.debian.org, under the
470 universe directory, and uses only files found under
471 unstable/binary-i386 on i386 machines, unstable/binary-amd64 on amd64,
472 and so forth for other supported architectures. [Note this example only
473 illustrates how to use the substitution variable; official debian
474 archives are not structured like this]
475 deb http://ftp.tlh.debian.org/universe unstable/binary-$(ARCH)/
477 Types: deb
481 URIs: http://ftp.tlh.debian.org/universe
482 Suites: unstable/binary-$(ARCH)/
483 Uses HTTP to get binary packages as well as sources from the stable,
485 testing and unstable suites and the components main and contrib.
486 deb http://deb.debian.org/debian stable main contrib
488 deb-src http://deb.debian.org/debian stable main contrib
489 deb http://deb.debian.org/debian testing main contrib
490 deb-src http://deb.debian.org/debian testing main contrib
491 deb http://deb.debian.org/debian unstable main contrib
492 deb-src http://deb.debian.org/debian unstable main contrib
493 Types: deb deb-src
495 URIs: http://deb.debian.org/debian
496 Suites: stable testing unstable
497 Components: main contrib
498
500 apt-get(8), apt.conf(5),
501 /usr/share/doc/apt/acquire-additional-files.md.gz
502
504 APT bug page[1]. If you wish to report a bug in APT, please see
505 /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.
506
508 Jason Gunthorpe
509 APT team
511
513 1. APT bug page
514 http://bugs.debian.org/src:apt
515APT 2.3.11 09 June 2021 SOURCES.LIST(5)