Now we have session management in the Dash. It is absurd to relearn the commands for the Dash because they use different names or have a space in it. All I suggest is to show the same search result for e. g.:
'shut down', 'shutdown' or 'halt'.
Alt+F2Is not the right place - IMHO. To shutdown the computer I would have to write:
'gksudo halt' → pw → press Enter
... this is way to long. I would prefer then the cog.
Dashopen Dash + tip 'halt' + two times Enter → much better and faster