How to kill or close a frozen window with xkill on Ubuntu

Sometimes some applications freeze and we cannot close them. In such case, we can use xkill command in terminal.

Run xkill

When you run xkill command, a "X" sign will appear on the screen as mouse pointer. If you move it on to the window you want to close and click once with your mouse, the window will close.

inanzzz@inanzzz:~$ xkill