A simple list of installed packages

max@wonko:~$ aptitude search '~i' -F '%p'

Search for installed packages from the testing repo

max@wonko:~$ aptitude versions '~i ~Atesting' --group-by=none

Finding why a package is installed

I found fonts-font-awesome in my headless server, but there’s a reason

max@wonko:~$ aptitude why fonts-font-awesome
i   owncloud Depends fonts-font-awesome

Select packages that were removed but not purged

max@wonko:~$ aptitude search '~c'

Search in the package description

max@wonko:~$ aptitude search '~d"web browser"'

Upgradable packages

max@wonko:~$ aptitude search '~U'