Here’s a list of common Mac OS X keyboard shortcuts.

Startup
Keystrokes Description
Press X during startup Force Mac to boot into Mac OS X when Classic is installed and set as the startup system.
Press Option-Command-Shift-Delete Bypass the startup disk set in the Startup Disk preference panel and boot from any other disk or volume with a viable Mac OS X operating system installed.
Press C during startup Start up from a CD or DVD that has a a viable system installed.
Press N during startup Attempt to start up from a compatible network server (NetBoot).
Press T during startup Start up in FireWire Target Disk mode.
Press Shift during startup Start up in Safe Boot mode and temporarily disable login items and non-essential kernel extension files (Mac OS X 10.2 and later).
Press Command-V during startup Start up in Verbose mode.
Press Command-S during startup Start up in Single-User mode.
Finder
Keystrokes Description
Command-W Close Window.
Option-Command-W Close All Windows.
Command-Right Arrow Expand Folder (list view).
Option-Command-Right Arrow Expand folder and nested subfolders (list view).
Command-Left Arrow Collapse Folder (list view).
Option-Command-Up Arrow Open parent folder and close current window.
Menu Commands
Keystroke Description
Apple menu
Shift-Command-Q Log out. Same as clicking Log Out… in the Apple menu. You’ll be asked if you want to quit all applications and log out.
Shift-Option-Command-Q Log out immediately.
Finder menu
Shift-Command-Delete Empty Trash
Option-Shift-Command-Delete Empty Trash without dialog
Command-H Hide Finder.
Option-Command-H Hide Others.
File menu
Command-N New Finder window.
Shift-Command-N New Folder.
Command-O Open.
Command-S Save.
Shift-Command-S Save as.
Command-P Print.
Command-W Close Window.
Option-Command-W Close All Windows.
Command-I Get info.
Option-Command-I Show Attributes Inspector.
Command-D Duplicate.
Command-L Make alias.
Command-R Show original.
Command-T Add to Favorites (Mac OS X 10.2.8 or earlier), Add to Sidebar (Mac OS X 10.3 or later—use Shift-Command-T for Add to Favorites).
Command-Delete Move to Trash.
Command-E Eject.
Command-F Find.
Edit Menu
Command-Z Undo.
Command-X Cut.
Command-C Copy.
Command-V Paste.
Command-A Select All.
View Menu
Command-1 View as Icons.
Command-2 View as List.
Command-3 View as Columns.
Command-B Hide Toolbar.
Command-J Show View Options.
Go Menu
Command-[ Back.
Command-] Forward.
Shift-Command-C Computer.
Shift-Command-H Home.
Shift-Command-I iDisk.
Shift-Command-F Favorites.
Shift-Command-G Go to Folder.
Shift-Command-K Connect to Server.
Window Menu
Command-M Minimize Window.
Option-Command-M Minimize All Windows.
Help Menu
Command-? Open Mac Help.
Miscellaneous
Comand-Space Open Spotlight (Mac OS X 10.4 and later).
Command-Esc Activates Front Row for certain Apple computers