http://www.perlmonks.org?node_id=1041786


in reply to Reaped: use of uninitialized value in array

First hint: the statement <FILE> reads the contents of FILE until the next newline, chomp removes that trailing newline, so as a result $_ will not contain any newlines afterwards. So your splitting on newlines makes no sense as neither $first nor $second (being parts of $_) will contain any newline.