So if you want to bind opening the system monitor, either change the shortcut binding for log out to something else, or use another shortcut. CTRL+ ALT+ DEL will bring you back to the default screen after 60 s, at least if the system hasn't hung, and will pop up a window prompting to cancel or confirm log out. As per this answer, after setting CTRL+ ALT+ Backspace to gsettings get -sources xkb-options, with the Brave browser open it just pulls down or up the menu toolbar, while with other applications it does nothing. On Ubuntu 17.10 with GNOME, ALT+ F4 is the default to close a window.
Wait a second between each presses, because each letter is a different kernel action leading to a "graceful" reset. This one is a bit hard to remember, but it involves pressing and holding Alt+ SysRq (system request, often same key as PrtScr print screen) and then press in order R, E, I, S, U, B (a mnemonic is Reboot Even If System Utterly Broken). 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.