Shortcuts on laptops

System startup

Hold down these keys to cause a Mac to perform special actions at startup time.

C	boot from CD or DVD
D	force the boot device to be the internal hard drive
T	start up in FireWire/Thunderbolt target mode (the Mac temporarily becomes a very expensive external FireWire/Thunderbolt drive)
X	force boot into Mac OS X (older Macs that dual-boot into OS 9 and X)
N	boot from Network drive
shift	hold after power-up to boot into safe mode, hold after login to prevent startup items from opening
mouse button	eject CD before booting normally
command-S	boot into single user mode; type exit when done
command-option-O-F	boot into the Open Firmware prompt
command-option-P-R	reset PRAM
command-option-V	verbose boot; show the Unixy text goodness at boot time
command-option-shift-delete	bypass internal hard drive and boot from external drive or CD
option	choose startup disk at boot time
command-.	when startup disk chooser is active, open the CD tray

Customizing shortcuts

Many system-wide shortcuts can be customized. This is described in detail in the Changing Keyboard Shortcuts article.

Shortcuts on laptops

On most Mac laptops, some of the function keys (F1 - F12) are used to control hardware features:

F1	decrease brightness
F2	increase brightness
F3	mute on G4s, decrease volume on G3s
F4	decrease volume on G4s, increase volume on G3s
F5	increase volume on G4s, numlock on G3s
F6	Num lock on G4s, mute on G3s
F7	Display mode (mirror or extend external display)
F8	disable backlit keyboards (Aluminum PowerBooks)
F9	decrease keyboard brightness for backlit keyboards
F10	increase keyboard brightness for backlit keyboards
F12	eject (some Macs, namely all MacBooks, MacBook Pros, and newer PowerBooks, place a dedicated eject key next to the F12 key)