Adding repositories in Ubuntu (command line)

The Basics

Ubuntu uses apt for package management. Apt stores a list of repositories or software channels in the file

/etc/apt/sources.list

By editing this file from the command line, we can add, remove, or temporarily disable software repositories.

•  Note: It's always a good idea to backup a configuration file like sources.list before you edit it. To do so, issue the following command:

  sudo cp /etc/apt/sources.list /etc/apt/sources.list.backup

Typically, the beginning of the file /etc/apt/sources.list looks like this:

# sources.list
#deb cdrom:[Ubuntu 13.10 _Saucy Salamander_ - Release i386 (20131016.1)]/ saucy main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted
deb-src http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted
#...

Explanation of the Repository Format

• All the lines beginning with one or two hashes (#) are comments, for information only.

• The lines without hashes are apt repository lines. Here's what they say:

  • deb: These repositories contain binaries or precompiled packages. These repositories are required for most users.

  • deb-src: These repositories contain the source code of the packages. Useful for developers. 

  • http://archive.ubuntu.com/ubuntu: The URI (Uniform Resource Identifier), in this case a location on the internet. See the official mirror list or the self-maintained mirror list to find other mirrors.

  • saucy is the release name or version of your distribution.

  • main & restricted are the section names or components. There can be several section names, separated by spaces.

Other Versions

•  For other Ubuntu releases you would replace the 'saucy' with the current version you have installed ('precise', 'quantal', 'raring', 'saucy', 'trusty', ...) Type lsb_release -sc to find out your release.

Adding Repositories

• sudo add-apt-repository "deb http://us.archive.ubuntu.com/ubuntu/ saucy universe multiverse"

• sudo add-apt-repository ppa:<repository-name>

Don't forget to retrieve the updated package lists:

• sudo apt-get update