sources.list

5 APT

sources.list

Package resource list for APT

## Description

The package resource list is used to locate archives of the package distribution system in use on the system. At this time, this manual page documents only the packaging system used by the Debian GNU/Linux system. This control file is `/etc/apt/sources.list`.

The source 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 format of each line is: `type uri args` The first item, `type` determines the format for `args`. `uri` is a Universal Resource Identifier (URI), which is a superset of the more specific and well-known Universal Resource Locator, or URL. The rest of the line can be marked as a comment by using a #.

## 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 they will be silently ignored.

## The deb and deb-src types

The `deb` type describes a typical two-level Debian archive, `distribution/component`. Typically, `distribution` is generally one of `stable` `unstable` or `testing` while component is one of `main` `contrib` `non-free` or `non-us`. The `deb-src` type describes 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 uri distribution [component1] [component2] [...]

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

`distribution` may also contain a variable, `$(ARCH)` which expands to the Debian architecture (i386, m68k, powerpc, ...) 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.

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.

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://http.us.debian.org/debian stable main contrib non-free
    deb http://http.us.debian.org/debian dists/stable-updates/

## URI specification

The currently recognized URI types are cdrom, file, http, ftp, copy, ssh, rsh.

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 CDROM 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 a ftp proxy can be specified by using the `ftp_proxy` environment variable. It is possible to specify a http proxy (http proxy servers often understand ftp urls) using this method and ONLY this method. ftp 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 a zip disk to copy files around with APT.

rsh

ssh

- The rsh/ssh method invokes rsh/ssh to connect to a remote host as a given user and access the files. It is a good idea to do prior arrangements with RSA keys or rhosts. Access to files on the remote uses standard `find` and `dd` commands to perform the file transfers from the remote.

more recognizable URI types

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

  `apt-transport-debtorrent`

  1.

## 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

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/contrib area.

    deb ftp://ftp.debian.org/debian stable 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 nonus.debian.org, under the debian-non-US directory.

    deb http://nonus.debian.org/debian-non-US stable/non-US main contrib non-free

Uses HTTP to access the archive at nonus.debian.org, under the debian-non-US directory, and uses only files found under `unstable/binary-i386` on i386 machines, `unstable/binary-m68k` on m68k, and so forth for other supported architectures. [Note this example only illustrates how to use the substitution variable; non-us is no longer structured like this]

    deb http://ftp.de.debian.org/debian-non-US unstable/binary-$(ARCH)/

## See Also

&apt-cache; &apt-conf;

&manbugs;