May 17, 2011, 11:45 AM — You've probably got the basics of the Application Switcher down pat by now: press Command-Tab to see a bar full of running-application icons and keep Command down as you tap the Tab key to quickly switch to the application of your choice. But, as with everything on the Mac, the Application Switcher can do more than you might guess.
One note: unless you're simply moving back and forth between two programs, press Command-Tab and then let go of Tab immediately to keep the Application Switcher on the screen. This lets you see where you're going, and approach more complex tasks, without the focus racing from one application icon to the next on the bar.
1. Quit all open applications
Say you want to install new software that requires you to quit all your programs. There's no need to move to every program and quit each individually. Press Command-Tab for the Application Switcher and then, keeping Command down, press and hold Q. Each application quits in turn; you'll be notified if there are any unsaved changes in documents.
2. Open a new window
Just as nature allegedly abhors a vacuum, users abhor a window-less application—after all, what can you do if there's nothing to work in? If you've left an application (Microsoft Word, for instance) with all its windows closed or minimized, you can use the Application Switcher to return to it with a window ready for you to work in.
Command-Tab to the program in question and, before you release the Command key, press Option. Release the Command key first, and then the Option key. (It's easier if you use the Option key on the opposite side of the spacebar instead of the one next to the Command key.) If the target program's windows are all minimized, the most recently minimized one returns to duty. If no windows at all are available, a new one is created. (Some programs interpret "new window" a little differently; Numbers, for instance, opens its Template Chooser for you to select from.)
3. Open a document in a different program
When you want to open a document in something other than its default application—a Word file in Pages, say—you can use variations of the Finder's Open With command. But if the target application is already open (and can handle the document), you can also just drag the file from the Finder onto the Application Switcher bar. The trick is to start the drag operation, and pause it with the mouse button held down, before you press Command-Tab; keep Command down so the bar stays on the screen, and drag the document onto an application's icon.
4. Bypass the Clipboard