+ # OK this is real tricky. If we call execute with a command of PS1=@@@
+ # and we've changed our prompt to '@@@' then we'll see the '@@@' in the
+ # PS1=@@@ statement as the prompt! That'll screw us up so we instead say
+ # PS1=\@\@\@. The shell then removes the extra backslashes for us and sets
+ # the prompt to just "@@@" for us. We catch that as our prompt and now we
+ # have a unique prompt that we can easily recognize.