Update your cache:
apt-get update
Get a list of all packages available, make sure to
apt-cache pkgnames > readme.txt
Install the following:
sudo apt-get install apt-show-versions
This allows you to show all versions installed:
apt-show-versions | sort > readme.txt
A couple of switches are available too:
-u (print only upgradeable packages)
There are more switches available, use apt-show-versions --help for more information.
Completely remove a package
apt-get --purge remove