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#http://askubuntu.com/questions/17823/how-to-list-all-installed-packages
apt --installed list

dpkg-query -Wf '${Installed-Size}\t${Package}\n' | sort -n
#dpkg --get-selections > ~/InstalledPackages.list

#or 
dpkg --get-selections | grep -v deinstall

#To save that list to a text file called packages on your desktop do this in your terminal:
dpkg --get-selections | grep -v deinstall > ~/Desktop/packages

#Alternatively, simply use
dpkg -l

#aptitude has its manner
aptitude search '~i!~M'