Kill Processes Quickly With PKILL
To kill a process I've always either used top, or the kill or killall commands along with ps|aux to discover process numbers/names. However, the pkill command removes a lot of work -- pkill firefox, for example, will search the list of processes for anything matching firefox, and then kill it (i.e. send a SIGTERM). pstree is also a pretty cool command, and will show all the processes in a family-tree arrangement, organized by who owns them."
From:
10 Expert Ubuntu Tricks - Business Center - PC World