"addachievement x" where x is a number between 1 and 54, corresponding to the game's 54 achievements. That's including the four added by Operation: Anchorage, which you don't even have to own to get the additional 100 potential points included in that add-on.
Taken from another forum out there.
McKillem posted on Oct 22, 2009 11:19:26 AM - Report post
Actually, there are 72 achievements right now - and all unlockable by "addachievement X".