Repositories

If you have been a Windows and/or a macOS user to date, you are probably used to finding a program on the internet, downloading it, and running an installer.

On Ubuntu, most software is packaged in files which contain the programs and libraries that you need. These files can be downloaded from software repositories, using the graphical Ubuntu App Center or using terminal commands.

This page contains a brief summary of what you need to know as a new user of Ubuntu, but you should refer to the official Ubuntu Project documentation for more detail.

Official Ubuntu Project documentation

For more detailed information about Ubuntu packages, repositories, components, pockets, and more, refer to https://ubuntu.com/project/docs/how-ubuntu-is-made/concepts/package-archive/.

Software in Ubuntu's repository is divided into four categories or components: main, restricted, universe, and multiverse.

The groups are distinguished by how reliably they can be maintained, who is primarily responsible for their maintenance, and whether they are open/closed source.

Below is a brief summary:

• Main: free and open-source applications that are free software, can be freely redistributed and are fully supported by Canonical.
• Restricted: close-source tools, codecs, and drivers. You can opt-in to install these when installing Ubuntu, or, as of Ubuntu 26.10, enable them in the Add-ons section of the Ubuntu App Center.
• Universe: free and open-source applications that are maintained by the Ubuntu community.
• Multiverse: applications that do not meet all the requirements to be open source.