I’ve been a Mac user since the Performa 638 CD I purchased in 1994, and I had no idea these shortcuts existed. While I wouldn’t recommend them to every Mac user, if you’re comfortable with the potential issues of immediately shutting down your Mac, you’ll want to learn these post-haste.
Note that when we refer to the Power button below, you may see an Eject button instead. Use either the Power or Eject button, whichever is in the upper right of your keyboard, to activate the following instant actions.
To reboot your Mac instantly, hit Control-Command-Power/Eject. To immediately shut down your Mac, hit Command-Option-Control-Power/Eject. To Log yourself (or any user) off of your Mac without using a menu or mouse, hit Command-Shift-Q.
To put your Mac right to sleep, the poor dear, hit Command-Option-Power, and hold them down for two seconds or so. To turn off your Mac’s display immediately, hit Shift-Control-Power. Go ahead, try it! To wake your screen back up, just hit the Spacebar key.
Now you have the magic keys to the kingdom, at least as far as shutting down or restarting your Mac on the fly without needing to use an onscreen button, mouse, or menu. Just remember that with great power comes great responsibility..