You may also be interested in `aptitude`, which is a command-line, "graphical" interface to the package manager. It can be installed with the following command:
sudo apt-get install aptitude
After running `sudo aptitude`, the following basic commands are used for navigation:
* `Ctrl-T`: open the menu bar.
* `+`: mark a package for installation.
* `-`: cancel the pending installation of a package.
* `g`: Proceed to the package selection confirmation screen.
* `g`: Press again to confirm your selection.
* `q`: Or press to close the current view and return to the package list.
These are the absolute basic operations, of course. For details, see the documentation:
Chapter 1 is a good starting point, and `aptitude` can really be a great tool to get to know!