Files with the .tar, .tgz, .tar.gz or .tar.bz2 suffix are package files known as tarballs, and are widely used in Linux and Unix to package software. Tarballs can also be used to archive and compress other files.

If there is no native Ubuntu package available in any of the Ubuntu repositories, you can use the command line to install or uninstall the tarball file.

The first step will be to uncompress and extract the tarball. If it is a .tgz or a .tar.gz, in a Terminal enter:

tar xfvz tarball_name

Then it will be necessary to follow the instructions that come with the package. These are generally located in the extracted tarball in a file called README or INSTALL. 

Tarballs often contain the source code of the program, and need to be compiled in order to be used.