not pressing and holding the power button). If even that doesn't work, the last thing you can do is ensuring a sane shutdown (i.e. If you have done that and your system later hangs, you can press Ctrl+ Alt+ Backspace, which will effectively bring you back to the login screen. One of the options is Key sequence to kill the X server, you can click that run gsettings get -sources xkb-options for recent versions of Ubuntu (according to this answer). The first has to be enabled in advance when your system doesn't hang yet (you could do it right now): open Keyboard Layout settings (I believe this is merged into Keyboard in Ubuntu 12.04), then click Options. If that happens, there are two things you can do. This is traditionally bound to Ctrl+ Alt+ Esc (not sure if by default) and allows you to click on a misbehaving window to close it.īoth of these might not work if your entire system hangs. You can set up keyboard shortcuts in the Keyboard settings (Shortcuts tab), so you can bind Ctrl+ Alt+ Del to gnome-system-monitor, the command to start System Monitor.Īnother command you might be interested in is xkill.
System Monitor shows you an overview of running applications (under the Processes tab) and allows you to end them by right-clicking on the name and selecting the respective context menu item.