The
sources.list file resides in the
/etc/apt directory. Like most other Linux
configuration files, it can be revised by using an ordinary text
editor, such as
ae.
The file contains a series of lines, each specifying a source
for packages. The lines are consulted serially, so it's usually
advantageous to place lines that specify local sources - such as a
CD-ROM - ahead of lines that specify remote sources. Doing so can
save many minutes of download time.
Each line has the form:
deb
uri distribution components
The
uri is a universal resource
identifier (URI) the specifies the computer on which the packages
reside, the location of the packages, and the protocol used for
accessing the packages. It has the following form:
protocol://
host/
path
Four protocols - sometimes called URI types - are
recognized:
-
cdrom
-
A local CD-ROM drive.
-
file
-
A directory of the local filesystem.
-
http
-
A Web server.
-
ftp
-
An FTP server.
The
host part of the URI and the
preceding pair of slashes (//) are used only for the
http and
ftp
protocols. There, the
host part of the URI
gives the name of the host that contains the packages.
The
path part of the URI always
appears, with the preceding slash (/). It specifies the absolute path
of the directory that contains the packages.
Here are some examples of typical URIs:
cdrom:/cdrom
cdrom:/mnt/cdrom
file:/mnt
file:/debian
https://www.us.debian.org/debian
https://non-us.debian.org/debian-non-US
ftp://ftp.debian.org/debian
ftp://nonus.debian.org/debian-non-US
The distribution part of a
sources.list
line specifies the distribution release that contains the
packages. Typical values include:
-
stable
-
The latest stable release; that is, one
that is commonly regarded as having sufficiently few serious bugs for
everyday use.
-
unstable
-
The latest unstable release. This release sometimes contains serious bugs and should not be installed by users who require high levels of system availability or reliability.
The components part of a
sources.list line
specifies the parts of the distribution that will be accessed. Typical
values include:
-
main
-
The main set of packages.
-
contrib
-
Packages not an integral part of the
distribution, but which may be useful.
-
non-free
-
Packages that contain software
distributed under terms too restrictive to allow inclusion in the
distribution, but which may be useful.
A typical
sources.list file might contain
the following entries:
deb file:/cdrom stable main contrib
deb https://www.us.debian.org/debian stable main contrib non-free
deb https://non-us.debian.org/debian-non-US stable non-US
This configuration allows rapid access to the distribution
packages contained on the local CD-ROM. It also allows convenient
access via the network to other packages and more recent package
versions stored on web servers.
Once you've configured sources.list, you can use
apt-get to update information on available
packages, to install a package, or to upgrade installed
packages.
To update information on available packages, issue the following
command:
apt-get update
To install a specified package, issue the following command:
apt-get install
package
where
package specifies the name of
the package to be installed.
To automatically upgrade all installed packages to the latest
available version, issue the following command:
apt-get upgrade
