Apt-get

apt-get is the command to initialize Debian's native package management utility/application "Apt". This tool has also been ported to a number of other distributions.

You use the apt-get command to install and remove software packages from your system (one at a time or many at once), as well as update your system's internal listing of what packages are available from your currently selected list or repositories.

Tips
to install a package:

to reinstall a package

to remove a package:

to remove a package and configuration file:

to search for a package:

to update the repository (list of avalible .deb's):

to upgrade your system (can be useful in maintaining an up-to-date system):

to upgrade your distribution (tries to choose packages needed to upgrade your dist):

to enable smart-tab completion, add the line

to your .bashrc file. When you enter a command like "apt-get install a ," bash will auto-complete the entry.

to see a short list of common commands:

Extra
Try running

Using with other distributions
You can go to Freshrpms to find apt-get tools for distributions other than Debian. After apt-get is installed, the command line syntax is the same as that listed above for Debian.

Trouble-shooting with RPM-based distributions
Sometimes apt-get will complain about being unable to lock a specific directory. Many of these problems can be remedied with the following commands.

rm /var/lock/rpm/transaction rm /var/lib/rpm/__db* rm /var/cache/apt/archives/lock