View all the packages installed on a system The easiest way to do it is:

dpkg --get-selections

List files which get installed by a package -L is a handy parameter to dpkg which will show you what files a package will install.

dpkg -L package_name

In case the package is not installed - try out:

apt-file list file_name

You may need to install apt-file first though.

Upgrade your system using a one-liner Type as root:

apt-get update && apt-get dist-upgrade

Sometimes you need to compile from source a newer version of an application which is already included in the repositories. For example, to install the development libraries for BasKet, you would run as root:

apt-get build-dep basket

Remove unused package files When you install software using APT, the DEB packages are kept inside the /var/cache/apt/archives directory. In time, the size of it could get very large. To clean the unneeded files:

apt-get clean

In case you want to have some more details - check out this link