In order to add or remove applications in Ubuntu you need to use a package manager. A package manager is a tool that makes installing and uninstalling applications easy by handling the software in preconfigured packages that are optimized for Ubuntu. The following package managers are described in this chapter:

You may also wish to increase the number of programs available to install through your package managers. Not all the programs that exist for Ubuntu are available by default. You may have to add extra repositories in order to make them available: that is also described in this chapter.

Finally, this chapter explains how to update your system.


You can only have one package management application running at a time. For example, if you are running Add/Remove Applications and try to launch Update Ubuntu, it will fail with an error. Close the running application before you relaunch the new one.