Enabling ubuntu - Debian additional repositories for apt

Posted on 6:54 PM by Bharathvn

The multiverse and universe repositories were not enabled by default. These repositories now come enabled by default with Ubuntu, so doing updates and searching for software will turn up many more options. One concern you may have, however, is that support, licensing, and patches may not be available for the universe and multiverse repositories. This could be a problem if you are considering an installation where you need to adhere to certain policies and procedures.

To disable the universe or muliverse repositories, open the file /etc/apt/sources
.list in a text editor and comment out the lines which have multiverse or universe
components enabled. You may want to initial the comments to make note of what you
commented out, as shown by the #cn in the following examples:

#cn deb http://us.archive.ubuntu.com/ubuntu/ feisty universe
#cn deb-src http://us.archive.ubuntu.com/ubuntu/ feisty universe
#cn deb http://us.archive.ubuntu.com/ubuntu/ feisty multiverse
#cn deb-src http://us.archive.ubuntu.com/ubuntu/ feisty multiverse
#cn deb http://security.ubuntu.com/ubuntu feisty-security universe
#cn deb-src http://security.ubuntu.com/ubuntu feisty-security universe
#cn deb http://security.ubuntu.com/ubuntu feisty-security multiverse
#cn deb-src http://security.ubuntu.com/ubuntu feisty-security multiverse

Likewise, if you want to add extra repositories that may be offered by individuals or
companies, you can do so by adding a line to the /etc/apt/sources.list file. To
edit this file, you must have root permissions:

$ sudo vi /etc/apt/sources.list

Insert a line starting with deb (for pre-built packages) or deb-src (for source packages), then the URL for the repository, along with the distribution (such as feisty above), and the component descriptions (universe in the examples). Typically, you'll describe components as contrib for contributed (that is, not from the Ubuntu project) and free or non-free. Normally, you should receive all this information from the site that offers the repository.

If you do add other third-party repositories, be sure to look into the authenticity of the entity offering the software before modifying your Linux system. Although it’s
not a big problem with Linux these days, it is easy to add broken or malicious software to your system if you do not exercise care and reasonable caution. Only use software from well-known sources, and always have a means to verify software you download prior to installing. For more information on software repositories,
see the Debian Repository HOWTO (www.debian.org/doc/manuals/repositoryhowto/

An example from the HOWTO document follows:

deb ftp://sunsite.cnlab-switch.ch/mirror/debian/ unstable main contrib non-free