Are you a Debian/Ubuntu Administrator or a regular user, then you may use the dpkg and APT commands often. These commands are used to install, remove, update or upgrade a package or the whole system. Mostly, we use the above two tools only for our day to day operations, But believe me, there are many useful commands are exist that most users aware of.
If you want to know which packages occupy the most disk space, or which package might have broken another, or to get a most recent version of a package, or just to get a particular version of a package, then you probably need Debian-goodies.
Full article here:
Debian-goodies: A must-have Set of Utilities For Debian/Ubuntu Administrators (Unixmen)