The command-line tool for handling software packages with apt, an integral part of the Debian GNU/Linux package management system. It primarily allows the user to update the indexes of available packages from the locations (remote sites on a network, CD-ROMs, hard drives, etc.) specified in sources.list, to download source packages, and to upgrade, install and remove packages. The apt database is a central list of package information, including their dependencies, that is independent of the individual packages. Among other things, this database specifies the packages that particular packages "Depend" on, "Recommend", or "Suggest". apt-get satisfies these dependencies during the upgrading, installation and removal of packages.
Installing a package on an apt-based distribution is simply accomplished with the command apt-get install pkgname. This will download and install the newest version of the specified package, as well as any other packages required by that package. Upgrading the entire distribution is accomplished easily as well, with the command apt-get dist-upgrade. apt will upgrade all the packages on the system that can be upgraded, and will satisfy the many dependencies involved in upgrading so many different packages. apt-get remove pkgname will remove the specified package, although it is often better to use apt-get remove --purge pkgname, which purges the configuration files in addition to removing the application.
See also: apt-cache
, ports collection