use strict; use warnings; my $count = 0; for my $s(chr(13) . chr(10), chr(10) . chr(13), chr(10) , chr(13) , '0' . chr(13) . chr(10), '0' . chr(10) . chr(13), '0' . chr(10) , '0' . chr(13) , ) { $count++; print "$count match\n" if ($s && $s =~ m![[:cntrl:]]+!); }