OS X: Ten Boot Options for Leopard
To use these boot shortcuts or commands, hold down the bolded keypress while your system is booting up. If it does not work, you probably did not start holding down the key (or key combination) soon enough.
shift – Safe Mode
Booting with the shift key depressed starts OS X in Safe Mode with Account preferences ignored and unessential kernal extensions / kexts disabled.
option – Startup Manager
Booting with the option key depressed starts OS X with the Startup Manager which allows the user to select which OS or partition from which to boot.
Mouse button – Eject Media
When the user boots with the mouse key depressed, any media in the drive such as a DVD or CD is ejected.
cmd v – Verbose Boot
If this key command is held down when booting, all the startup messages that are typically hidden will be displayed. This is an excellent method for debugging booting issues.
c – Boot from CD/DVD
Booting with the “C” key held will tell the system to boot directly from a CD/DVD in the drive.
t – Target Mode
If the “T” key is held during the bootup, the computer will be placed in target mode. This basically allows the computer to be accessed by other systems as a FireWire drive. Other computers can read, write, or mount the target mode system just like any other FireWire drive.
Other Bootup Shortcuts —
cmd s – Single User Mode
x – OS X Force boot
r – PowerBook Display Reset
n – Boot up from NetBoot Server