http://www.perlmonks.org?node_id=484936


in reply to Is it a list or a flip-flop?

You are using the .. operator in scalar context. When you do this, and have a number at one end, it compares that number to $. (the current line of the selected file handle, usually used in a while (<FH>) {} loop. Since you aren't reading a file, $. is uninitialized at this point.