In linux, graphical interface of console there is also a program who can listing all program running in background or front like windows task manager. I m using konsole not kde graphical. As far as I know, you should install software like ktop for kde.
here what you should do in konsole
the listing program will running, including the latest program you just run. As you can see, there are several columns displayed. The most things that we need to pay attention are : PID, USER and COMMAND.
To end the top command, type q (means quit).
If we need to shutdown some process using kill command, we need to know the PID for the program/ command.
Then run this
3201 is the example of PID of some program.
The kill command always work to shutdown any program that running in Linux. Even the program hangs.