Mac OS X: Remove duplicated "Open with" menu items by rebuilding LaunchServices database

The "Open with" menu may contain duplicated items when you upgrade the application to a new version. For example, I upgraded my Firefox.app from 10 to 11, then 12. The Open With menu then contains three duplicated Firefox.app items. To clean them up, you can rebuild the LaunchServices database:

• On Mac OS X 10.5 or later (Leopard, Snow Leopard, Lion or Mountain Lion), run the following command:

  /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
  

• On Mac OS X 10.3 or 10.4 (Panther or Tiger), run the following command:

/System/Library/Frameworks/ApplicationServices.framework/\Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user