sources.list

5 APT

sources.list

List of configured APT data sources

## Description

The source list `/etc/apt/sources.list` is designed to support any number of active sources and a variety of source media. The file lists one source per line, with the most preferred source listed first. The information available from the configured sources is acquired by `apt-get update` (or by an equivalent command from another APT front-end).

Each line specifying a source starts with type (e.g. `deb-src`) followed by options and arguments for this type. Individual entries cannot be continued onto a following line. Empty lines are ignored, and a `#` character anywhere on a line marks the remainder of that line as a comment.

## sources.list.d

The `/etc/apt/sources.list.d` directory provides a way to add sources.list entries in separate files. The format is the same as for the regular `sources.list` file. File names need to end with `.list` and may only contain letters (a-z and A-Z), digits (0-9), underscore (_), hyphen (-) and period (.) characters. Otherwise APT will print a notice that it has ignored a file, unless that file matches a pattern in the `Dir::Ignore-Files-Silently` configuration list - in which case it will be silently ignored.

## The deb and deb-src types

The `deb` type references a typical two-level Debian archive, `distribution/component`. The `distribution` is generally an archive name like `stable` or `testing` or a codename like `&stable-codename;` or `&testing-codename;` while component is one of `main`, `contrib` or `non-free`. The `deb-src` type references a Debian distribution's source code in the same form as the `deb` type. A `deb-src` line is required to fetch source indexes.

The format for a `sources.list` entry using the `deb` and `deb-src` types is:

    deb [ options ] uri suite [component1] [component2] [...]

Alternatively a rfc822 style format is also supported:

         Types: deb deb-src
         URIs: http://example.com
         Suites: stable testing
         Sections: component1 component2
         Description: short
          long long long
         [option1]: [option1-value]

         Types: deb
         URIs: http://another.example.com
         Suites: experimental
         Sections: component1 component2
         Enabled: no
         Description: short
          long long long
         [option1]: [option1-value]

The URI for the `deb` type must specify the base of the Debian distribution, from which APT will find the information it needs. `suite` can specify an exact path, in which case the components must be omitted and `suite` must end with a slash (`/`). This is useful for the case when only a particular sub-section of the archive denoted by the URI is of interest. If `suite` does not specify an exact path, at least one `component` must be present.

`suite` may also contain a variable, `$(ARCH)` which expands to the Debian architecture (such as `amd64` or `armel`) used on the system. This permits architecture-independent `sources.list` files to be used. In general this is only of interest when specifying an exact path, `APT` will automatically generate a URI with the current architecture otherwise.

In the traditional style sources.list format since only one distribution can be specified per line it may be necessary to have multiple lines for the same URI, if a subset of all available distributions or components at that location is desired. APT will sort the URI list after it has generated a complete set internally, and will collapse multiple references to the same Internet host, for instance, into a single connection, so that it does not inefficiently establish an FTP connection, close it, do something else, and then re-establish a connection to that same host. This feature is useful for accessing busy FTP sites with limits on the number of simultaneous anonymous users. APT also parallelizes connections to different hosts to more effectively deal with sites with low bandwidth.

`options` is always optional and needs to be surrounded by square brackets. It can consist of multiple settings in the form ``setting`=`value``. Multiple settings are separated by spaces. The following settings are supported by APT (note however that unsupported settings will be ignored silently):

- `arch=`arch1`,`arch2`,…` can be used to specify for which architectures information should be downloaded. If this option is not set all architectures defined by the `APT::Architectures` option will be downloaded.

- `arch+=`arch1`,`arch2`,…` and `arch-=`arch1`,`arch2`,…` which can be used to add/remove architectures from the set which will be downloaded.

- `trusted=yes` can be set to indicate that packages from this source are always authenticated even if the `Release` file is not signed or the signature can't be checked. This disables parts of &apt-secure; and should therefore only be used in a local and trusted context. `trusted=no` is the opposite which handles even correctly authenticated sources as not authenticated.

It is important to list sources in order of preference, with the most preferred source listed first. Typically this will result in sorting by speed from fastest to slowest (CD-ROM followed by hosts on a local network, followed by distant Internet hosts, for example).

Some examples:

    deb http://ftp.debian.org/debian &stable-codename; main contrib non-free
    deb http://security.debian.org/ &stable-codename;/updates main contrib non-free

## URI specification

The currently recognized URI types are:

`file`

- The file scheme allows an arbitrary directory in the file system to be considered an archive. This is useful for NFS mounts and local mirrors or archives.

`cdrom`

- The cdrom scheme allows APT to use a local CD-ROM drive with media swapping. Use the &apt-cdrom; program to create cdrom entries in the source list.

`http`

- The http scheme specifies an HTTP server for the archive. If an environment variable `http_proxy` is set with the format http://server:port/, the proxy server specified in `http_proxy` will be used. Users of authenticated HTTP/1.1 proxies may use a string of the format http://user:pass@server:port/. Note that this is an insecure method of authentication.

`ftp`

- The ftp scheme specifies an FTP server for the archive. APT's FTP behavior is highly configurable; for more information see the &apt-conf; manual page. Please note that an FTP proxy can be specified by using the `ftp_proxy` environment variable. It is possible to specify an HTTP proxy (HTTP proxy servers often understand FTP URLs) using this environment variable and only this environment variable. Proxies using HTTP specified in the configuration file will be ignored.

`copy`

- The copy scheme is identical to the file scheme except that packages are copied into the cache directory instead of used directly at their location. This is useful for people using removable media to copy files around with APT.

`rsh`

`ssh`

- The rsh/ssh method invokes RSH/SSH to connect to a remote host and access the files as a given user. Prior configuration of rhosts or RSA keys is recommended. The standard `find` and `dd` commands are used to perform the file transfers from the remote host.

adding more recognizable URI types

- APT can be extended with more methods shipped in other optional packages, which should follow the naming scheme `apt-transport-`method``. For instance, the APT team also maintains the package `apt-transport-https`, which provides access methods for HTTPS URIs with features similar to the http method. Methods for using e.g. debtorrent are also available - see &apt-transport-debtorrent;.

## Examples

Uses the archive stored locally (or NFS mounted) at /home/jason/debian for stable/main, stable/contrib, and stable/non-free.

    deb file:/home/jason/debian stable main contrib non-free

As above, except this uses the unstable (development) distribution.

    deb file:/home/jason/debian unstable main contrib non-free

Source line for the above

    deb-src file:/home/jason/debian unstable main contrib non-free

The first line gets package information for the architectures in `APT::Architectures` while the second always retrieves `amd64` and `armel`.

    deb http://ftp.debian.org/debian &stable-codename; main
    deb [ arch=amd64,armel ] http://ftp.debian.org/debian &stable-codename; main

Uses HTTP to access the archive at archive.debian.org, and uses only the hamm/main area.

    deb http://archive.debian.org/debian-archive hamm main

Uses FTP to access the archive at ftp.debian.org, under the debian directory, and uses only the &stable-codename;/contrib area.

    deb ftp://ftp.debian.org/debian &stable-codename; contrib

Uses FTP to access the archive at ftp.debian.org, under the debian directory, and uses only the unstable/contrib area. If this line appears as well as the one in the previous example in `sources.list` a single FTP session will be used for both resource lines.

    deb ftp://ftp.debian.org/debian unstable contrib

Uses HTTP to access the archive at ftp.tlh.debian.org, under the universe directory, and uses only files found under `unstable/binary-i386` on i386 machines, `unstable/binary-amd64` on amd64, and so forth for other supported architectures. [Note this example only illustrates how to use the substitution variable; official debian archives are not structured like this]

    deb http://ftp.tlh.debian.org/universe unstable/binary-$(ARCH)/

## See Also

&apt-cache; &apt-conf;

&manbugs;