to get a pid, enter this
If you want to get the pid for a specific program, for instance xmms, enter this
To just kill an app that is hanging, from a shell enter xkill then click on the window of the program you want to kill.
Or, from the KDE desktop, hit ctrl-alt-esc, then click on the window that you want to kill.
Or, you can use the top function and if the pid is visible in the window just type k followed by the pid.
Or, you can use the gnome system monitor (which is how I frequently do it even though I run KDE).
Or, if you are running KDE, from a blank section of desktop, you can hit Ctrl-Esc and wait a few seconds for the KDE task manager to start and use it to kill the process.
So many ways to kill...so little time...