Based on the code you gave, you may want to look at the unix command 'split' before you spend too much time on this, if the only requirement is that each file be 200 lines.

If you're on a system that doesn't have it, go with the logic that RazorbladeBidet posted -- to get it from pseudocode to running, you'll want to change the print line to print OUTPUT $_; (there might be something else, as I haven't tried it either)