Here are a few keyboard shortcuts command; you can use to perform common tasks quickly.

[Ctrl] + [Alt] + [Backspace] = kills your current X session. Kills your graphical desktop session and returns you to the login screen.
[Ctrl] + [Alt] + [Delete] = From a non-graphical shell prompt, shuts down your Red Hat Enterprise Linux system. Use only when the normal shutdown procedure does not work. In a graphical desktop session, this shortcut displays the desktop logout screen that allows you to logout, reboot, or shut down your system. Erectieproblemen psychisch