On the Mac (as with Windows and Linux desktops), you have two ways to invoke 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.
Aside from its application menu, the Finder has these menus in its menu bar:
The Finder’s application menu
The commands found in these menus are highlighted in Tables 2-4 through 2-10. While most of these commands function the same across all applications, the functions of some, such as -B and -I, can vary between programs, and others may work only when the Finder is active. For example, -B in Microsoft Word turns on boldface type or makes a selection bold, while in Xcode, -B builds your application. Likewise, -I in Word italicizes a word or selection, while hitting -I after selecting a file, folder, or application ...