On the Mac (as with Windows and Linux desktops), you have two ways of invoking commands in the GUI: by using the menus or by issuing shortcuts for the commands on the keyboard. Not every menu item has a keyboard accelerator, but for the ones that do—the more common functions—using the keyboard shortcuts can save you a lot of time.
Table 2-4 lists the common key commands found in Mac OS X. While most of these commands function the same across all applications, the functions of some, such as
-I, can vary between programs, and others may only work when the Finder is active. For example,
-B in Microsoft Word turns on boldface type or makes a selection bold, while in Project Builder,
-B builds your application. Likewise,
-I in Word italicizes a word or selection, while hitting
-I after selecting a file, folder, or application on the Desktop ...