I need new tires on my truck.
Can you be a bit more specific? Any command that would shut down
SketchUp would have to be a system command, therefore, you are either
Windows or Mac. Do tell.
Are you wanting this to be executed from within a Ruby script called
by SketchUp, or a Ruby script that runs outside of SketchUp?
Why do you want to shut SketchUp down programatically?