Software repositories

A software repository is a place from which you can download and install software over the Internet.

There are thousands of programs available to install on Ubuntu. These programs are stored in software archives (repositories) and are made freely available for installation over the Internet. This makes it very easy to install new programs in Linux, and it is also very secure, because each program you install is built specially for Ubuntu and checked before it is installed.

To organise the software, Ubuntu repositories are categorised into four groups: Main, Restricted, Universe, and Multiverse. The rationale used to determine which software goes into which category is based on the level of support that software development teams provide for a program and the level of compliance the program has to the Free Software Philosophy.

The standard Ubuntu Install CD contains some software from the Main and Restricted categories.

If your system is connected to the Internet, many more software programs are made available for installation. For example, the “Universe” and “Multiverse” repositories are only available over the Internet.

[Warning]

The Multiverse repository contains software which has been classified as non-free. This software may not be permitted in some jurisdictions. When installing each package from this repository, you should verify that the laws of your country permit you to use it. Also, this software may not include security updates.

You can find more information about the Repositories available on the website.