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Simple question. I was about to assign the Ctrl+Alt++ keyboard shortcut to increase the volume, but I then realized it was already assigned for something. If I press this key combination the screen flashes black for a second, and then comes back. Pressing Ctrl+Alt+- produces similar behavior. So I'm curious, what's this shortcut supposed to do?

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up vote 8 down vote accepted

Ctrl + Alt + F1 through F12 are mapped for switching between virtual consoles. Your graphical display is usually mapped to vt7 or vt8, so F7 or F8.

Ctrl + Alt + BkSp aborts your graphical server and kills all graphical processes.

Ctrl + Alt + - and + switch to a smaller or higher screen resolution, respectively.

Ctrl + Alt + Esc runs xkill by default. The next window you click is killed.

There are several others, but I can't recall them.

If you want to map +/- to something, I'd suggest using the Windows key as a modifier, if you have one. It's treated as a "Super" Meta-key, and doesn't normally have any mappings at all.

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CTRL+ALT+BACKSPACE and CTRL+ALT+ESC are disabled by default in Ubuntu. – Javier Rivera Sep 10 '10 at 15:24
It is probably worthwhile to note that Ctrl-Alt-F1 is caught by the operating system and are best not messed with and Ctrl-Alt-+ is caught by the XServer which is more configurable, and less critical especially if (like many) you don't switch resolutions. – msw Sep 10 '10 at 17:41

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