To shut down a running Linux system, you must not reboot with the reset switch on the front or back of your computer, or just turn off the computer. Linux must be shut down in a controlled manner, otherwise files may be lost and disk damage incurred. You can press the key combination Ctrl Alt Del or Control Shift Power on Macintosh systems. You may also log in as root and type shutdown -h now, reboot, or halt if either of the key combinations do not work or you prefer to type commands.