Xterm for beginners
apt-get update = updates local metadata detailing what apps are available in the repsitories
apt-get upgrade -y = upgrades any installed apps with newer versions (the -y is optional and just avoids it prompting you as to whether or not to proceed)
apt-get clean = will remove any dowmloaded package archives. Once the package is installed the dowmloaded file is no longer needed. The App Man does this automatically but if you're using "apt-get" you'll have to do it manually
apt-get autoclean = same as "apt-get clean" but only removes package archives which are obsolete (no longer in repsitories). Having run "apt-get clean it's pointless to run this command.
apt-get autoremove = removes any packages which are no longer needed. These are applications/libraries which were automatically installed because of dependencies but are no longer required
apt-get -f install = installs any missing dependencies (which should fix the broken packages issue I had)
dpkg --configure -a = fixes broken packages
ls -laS / or ls -laS /home/user or ls -laS/home/user/opt = shows you your biggest folders/files in the different locations
rm -r = removes all files or folders in a specific location
rm = removes singular file/folder from a location e.g. "rm -r /home/opt/themes" deletes all folders in the "themes" folder
[tab] key in X Terminal autocompletes words e.g. "rm -r /home/opt/themes/sun[tab] will finish the word as "sunset". Double [tab] would give you all the files starting with "sun". "rm -r /home/opt/[tab][tab] shows you what's in that "themes" folder
dpkg -l = shows you a list of all your programmes including those not visible in App Man
dpkg -P = removes the programme and all its configuration files e.g. "dpkg -P zenbound" uninstalles zenbound
find / = search for a file or folder in the complete system
find /home/user = search for a file or folder in /home/user
| grep <name> = what you're looking for e.g."dpkg -l |grep zen" lists all files in the system starting with "zen"
dpkg -l | awk '{print $2}' grep zen = nicer view
find / |grep zen = find all files with the "zen" beginning
rm -rf /home/opt/rovio/angrybirds/data/levels/pack2 = removes "mypack" custom levels
mkdir /home/opt/rovio/angrybirds/data/levels/pack2 = makes folder called "pack2"