Enable Single Application Mode in Mac OS X

What is Single Application mode?

Single Application Mode is a way to force Mac OS X to show only the application that is currently in use, all other open applications and windows will be minimized into the Dock. Selecting another application from the Dock will then minimize the current application, and the new selection becomes the only thing on screen. I have heard this feature was originally intended for presentation purposes when showing off Mac OS X, but it’s actually a handy way to avoid distractions and maximize screen space on smaller resolution displays.

How to enable Single Application mode in Mac OS X

Enabling this feature is done through the command line, so launch the Terminal then enter the following commands exactly:
defaults write com.apple.dock single-app -bool true
For this to take effect, you now must kill the Dock:
killall Dock

You can reverse single application mode and get back to multiple application mode easily by changing the original command as follows:
defaults write com.apple.dock single-app -bool false
and again, killing the Dock:
killall Dock

If you ask me, this feature is most useful for those with limited screen real estate or a single monitor, it’s actually kind of obnoxious if you have dual displays on your Mac.