I noticed. I am able to select for positive integers, but thats about it! When I try to do something like its just no go! This is probably fraught with mistakes, going from memory, but I'm sure you get the point Bang line $value1=shift $value2=shift unless (($value1 >= 0) or ($value1 <= 0) or ($value2 >= 0) or ($value2 <= 0)){ die; $sum "blah blah"; print "blah blah sum";