I am searching for a newuser-friendly way to kill non-responsive GUI applications under Unity.

I looked over the shoulder of a new Unity user who tried to use gscan2pdf - and gscan2pdf seems to be really broken - after not much tinkering it consumed much CPU und memory, the PC began trashing and the user needed to immediately kill the gscan2pdf GUI which was full-screen, non-responsive and had the focus.

Ok, I know some ways how to do it:

  • Hit Alt+F2 and type xkill -> select the window
  • Hit Alt+F2 start xterm, use top or pgrep and then kill PID or directly use pkill

Both are ways which are not very intuitive for GUI centric users.

Is there some Unity shortcut to get something like xkill?

Or is the best GUI-way to add a top-like GUI to the Unity-starter? And which one?

  • 3
    You could define a shortcut keybinding for xkill.. Dec 27, 2011 at 13:04
  • @nitstorm, ok, post how to do it as answer and I'll up-vote it. Dec 27, 2011 at 13:10
  • Posted with screenshots. Dec 27, 2011 at 13:26
  • I didn't even know about the xkill thing... Oct 28, 2014 at 12:12

5 Answers 5


You could create a keyboard shortcut for xkill.

  1. Type keyboard in the Unity Dash and click the icon. Select the shortcuts tab.

  2. There, scroll down to the custom shortcuts section and click on the + button

  3. Now name your shortcut something and let the command be xkill and then click ok.

  4. Finally click on the xkill shortcut and press the desired key-combo to assign a shortcut to it and that's it :)
  5. Pressing the keyboard shortcut will activate xkill whenever you need it.



  • 1
    An addition: To cancel an xkill, just right click anywhere and the cursor will change from a cross to the default arrow.
    – Parto
    Jun 13, 2014 at 21:40

The best way I find is using terminal window :

goto terminal :

sudo ps -aux | grep "name of application"

note down the process ID

sudo kill -9 "processID"

since, If GUI application becomes unresponsive, for time-being it slows down the X(GUI) and all actions would be slowed down, so any gui action for closing the process will be slow.

  • 1
    The OP doesn't want the kill command, he has specifically stated so in the second bulleted point. Dec 27, 2011 at 13:05
  • Wow, this is bad advice on several different levels - 1. I asked for a GUI or GUI-relatic solution for killing a task 2. ps ... | grep - there is the command pgrep, which is also mentioned in the question 3. kill -9 sends SIGKILL under which the program has no chance to terminate in a gracious way - usually one should always try kill PID first - this sends SIGTERM - only if the process does not terminate on SIGTERM, one should issue a kill -9 PID Dec 27, 2011 at 19:30
  • Also, I returns too many numbers. I don't think novices will easily find the PID without help. Aug 18, 2016 at 2:49

Another thing you can do is to run System Monitor. You can select a process with the mouse and hit the "End Process" button to kill it. This should even work with unresponsive processes but I don't think it is as strong as kill -9. It does have the advantage that it is a totally GUI solution and is very similar to the analogous Activity Monitor in Mac OS X. That's helpful to those of us who move back and forth between Mac and Linux.


Didn't try it by myself, but this small script looks useful. It adds a "Force quit" option to the unity launcher.


Script to send SIGTERM to the currently active window based on a similar question.

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