Apt-usage

Install package

apt-get install <packagename>

search package

apt-cache search <packagename> or <packagedescription>

remove package

apt-get remove <packagename> to remove but letting configfiles untouched

apt-get purge <packagename> to remove with configfiles and without checking dependencies

apt-get autoremove remove unneccesary Packages

Update Package-Cache

apt-get update

Upgrade Packages

and (without installing additional) dependencies

àpt-get upgrade

can lead to breaking. To install needed dependencies do:

apt-get install -f

Upgrade whole OS

apt-get dist-upgrade