Mac Keyboard Guide
Introducing the Mac Keyboard
Since the original iMac adopted USB in 1997, Apple has handily supported the USB Human Interface Device (HID) standard. If you have a generic USB PC keyboard handy, just plug it into your Mac mini and start typing.
However, Apple keyboards have keys you may not be used to seeing—there's that one with the Apple, the one called "Option", and Control-C doesn't seem to do anything. Just what are those keys, and what do they do?
Apple Command Key
First, the Command key. This key is used, in concert with other characters, to issue commands to an application. Its closest counterpart in Windows is the Control key; the two platforms often use the same cohort key for a particular function: CMD-P for Print, CMD-C for Copy, CMD-V for Paste, etc. The Command key is immmediately adjacent to the space bar and bears two symbols: an Apple logo and something that resembles a four-leaf clover.
Some refer to the Command key the “Apple key”, thereby belying their long affiliation with Apple hardware. (The Apple ][ computers had “open” (outline) and “closed” (solid) Apple keys, each of which performed different functions.) Some, including Apple’s documentation, refer to the symbol as a “cloverleaf”. The symbol is actually called the St. Hannes Cross, and is used in Scandinavian countries to denote roadside points of interest. The symbol was drawn by bitmap graphic designer Susan Kare. Ms. Kare confirms in an email that she drew it after finding "a similar symbol in a book that referred to it as a symbol to note a 'remarkable feature' at Swedish campgrounds."
PC+Mac Key Equivalents
Apple
PC
Next comes the Option key, which most closely matches the PC’s ALT key. The Option key is used to send an alternate character sequence, as in the case of an accented E (é). Increasingly, it is also used in concert with the Command key for an alternate command sequece. (For instance, in the Finder you press CMD-H to “Hide Finder”, while Opt-CMD-H is used to “Hide Others”.) Apple kindly includes the ALT label on the Option key.
Apple includes the familiar Control key, but it is largely unused in Mac OS X’s graphical interface. The key remains useful for shell commands and the Terminal application, but that’s about it.
Last, the Eject button. Newer Apple computers don’t have an external hardware eject button for the optical drive. This change allows for nicer aesthetics, but is, let’s face it, somewhat annoying. Apple mitigates this with a dedicated Eject button. Their 101-key keyboard puts this key at the top-right, above the numeric keypad’s asterisk; it is demarked with the arrow-and-bar symbol you’re used to seeing on VCRs and DVD players. On laptops, the Eject is overlaid on the F12 key.
Like their PC counterparts, Apple laptops have hardware interface functions overlaid on F-keys. These keys control display brightness, sound volume and mute. Volume keys are also included on Apple’s 101-key keyboard, again above the numeric keypad.