How to Kill an Unresponsive Process in Ubuntu Using the Terminal

When a graphical application freezes in Ubuntu and you cannot close it normally, you can use the terminal to force kill the unresponsive process immediately.

Using the kill command

1. Open your terminal.
2. Type xkill and press Enter. Your cursor will turn into an “X”.
3. Click on the frozen window to instantly kill it.
4. Alternatively, type htop, find the process ID (PID) of the frozen app, and type kill -9 PID to force terminate it.