open(my $in, "<", $inputfile) or die "Can't read '$inputfile': $!";
open(my $out, "<", $outputfile) or die "Can't read '$outputfile': $!";

binmode($out);
while (my $line = <$in>) {
  $line =~ s/\r\n?/\n/g;
  print $out $line;
}
close($in) or die "Can't close '$inputfile': $!";
close($out) or die "Can't close '$outputfile': $!";