exists command - resolution

[Brian K. White]

Just for the record, Dennis is stuck on 4.8, so my example based on @once 
needs slight adjustment,

Set a variable and test for it to simulate the effects of @once
just prepend  these 2 lines to the top of the table I posted:

  if: x ne "1"
  then: gosub @once
  if:
  then: x(1,*,g) = "1"

I'd actually change the lable of @once to just "once", so that when you do
eventually upgrade to 5.0 it won't start running @once twice all of the
sudden. Not that it would really hurt anything, since once it runs once, the 
file exists, and so the second time it runs it will always do nothing.