If you’re used to using Windows on your PC, the term “Force Quit” may not make much sense to you. But you probably know what it is … on Windows, you do it by hitting Ctrl-Alt-Delete, then selecting the Task Manager (if you’re on Windows Vista or Windows 7), then selecting the app that you want to kill. Sometimes when things crash, there’s just no other way.
Ubuntu lets you force quit applications too, and it even has a way to reset the panel in case that gets messed up somehow. But if you try Ctrl-Alt-Delete on the latest version of Ubuntu, Maverick Meerkat, it just brings up the shutdown dialog. How do do force quit an app in Ubuntu?
The hard way
As with so many other things in Ubuntu, force quitting an application can be done using a terminal command. Open a terminal (it may take a minute if your system’s slowed down from an unresponsive app), then type “xkill” without the quotation marks. Your mouse cursor will turn into an X. Just click on the app to force quit, and that should take care of it. (If you change your mind, right-click to turn the mouse cursor back.)
The easier ways
There are easier ways to force quit apps, of course. Hit Alt-F2 to bring up the “Run Application” dialog, then type xkill there and hit enter. Or if you use GNOME Do, you can type xkill into it if you have the GNOME Terminal plugin installed (go to Preferences -> Plugins from the arrow menu in the upper-right part of the GNOME Do box). Just make sure that the right-hand pane shows the “Run” action when you type xkill.
The panel applet
Right-click on an empty space on one of your panels (the bars at the top and/or bottom of your screen in Ubuntu) and select “Add to panel,” then select “Force Quit.” Now you’ve got an icon you can click to force quit anything! It’s brightly-colored and doesn’t blend with the new monochrome icons, though, so if you’re into making your Ubuntu Mac-like this might not be for you.
The last resort
If that doesn’t solve your problem, or the app keeps crashing when you try to restart it, go to System -> Administration -> System Monitor from the menu (again, GNOME Do makes this easier). After that, go to the Processes tab, and look for the name of the application you want to force quit. Click on it (it may have more than one entry), and select “End Process” for each entry. This is the equivalent of the Windows Task Manager, and you may have to use it sometimes.
Restarting a panel
If one of your panels goes all weird on you, you may have to manually add and reposition the applets. First, though, try resetting them to see if that fixes it. Open a terminal window, and type “killall gnome-panel” without the quotation marks. This resets all your panels; you’ll see them disappear, then reload.
Most of the time, you won’t need these instructions when using Ubuntu. But when you do need to force quit an application or reset the panels, it’s good to know how!
Either way, good luck, and I hope you have fun with Ubuntu!