Another alternative is to run 'top'.
I'm assuming your distro has 'top' installed.
'top' will list all the running process in realtime and the defualt kill signal I believe is '15'.
Read the 'top' man page (man top) and that'll getya going.
Another thing you can do ( just for the sake of learning) is from a command line---: kill -l
That'll list all the SIG*** options for killing a process, etc.
I hope I presented this so its clear and it does'nt seem like Martian hieroglyphics!