Apple - How can I kill a non-responding app?

You can access the Force Quit dialog box by pressing ⌘+⌥+esc, or using the Apple Menu (top left corner of the screen) and choosing Force Quit.... Select the problem app, and click the Force Quit button.

You can also kill an app using the command line (/Applications/Utilities/Terminal):

killall 'Google Chrome'

You can also use the Activity Monitor app (/Applications/Utilities). Select an app and click the Quit button: Then, from the dialog that slides down, click Force Quit.

Another way from the Terminal:

ps auxww | grep -i 'google chrome' | grep -v grep | awk '{ print $2 }' | xargs kill

Or to force kill:

ps auxww | grep -i 'google chrome' | grep -v grep | awk '{ print $2 }' | xargs kill -9 

This can be helpful if the screen isn't responding or you get Spinning Wheel of Death, but are able to somehow get to the terminal (e.g.: via SSH)

The "kill" command also exists in OS X (check out "man kill"); you can also kill an app using a couple of GUI-based tools:

1. press ⌘+⌥+esc. That brings up a "force quit" menu
2. launch the Activity Monitor application. You can also force-quit an app from there.