/Command (devenv.exe)
Visual Studio 2008
Executes the specified command after launching the Visual Studio integrated development environment (IDE).
devenv /command CommandName
After startup is complete, the IDE executes the named command. If you use this switch, the IDE does not display the Visual Studio Start Page on startup.
If an add-in exposes a command, you can use this switch to launch the add-in from the command line. For more information, see How to: Control Add-ins with the Add-In Manager.