How force quit (end process) an application?

[6tr6tr]

How do I end a running process like in Windows Task Manager?

[oz]

Go to a konsole/terminal and enter ps ux for all processes running by the current user:

ps ux

Identify the PID of the process you want to kill, then...

kill -9 xxxx

...replacing the xxxx with the process you want to stop.

You can also run top within the konsole/terminal to see processes running and do some process killing from there.

[sdimhoff]

if you know the name of the process you can use a kill derivative, killall

example:
$ killall firefox

Will kill all processes called firefox. There are also task manager-like gui's. An example for kde is KSysGuard, but there are several others available as well.