in reply to $ARGV dilemma

UPDATE: Err, I answered my own question right after submission; I apologize for asking such a silly question, and jumping to ask, before giving it any thought.
The solution is, of course, to just use unless $ARGV[2].

UPDATE 2: I guess I should have been more precise in both my question and update. Originally, the last argument was 0; but changing it to a string was the solution I came up with..