Possibly a Mac issue, but not a Windows issue. Perl's IO processing will already have converted CRLF to \n under Windows. The code I posted was tested using Windows.

However I agree that your regex solution is likely to be better. I'd avoid the "numeric" version though. That makes it more, rather than less, sensitive to OS and character sets.

Perl converts native line ends to \n (which may or may not be an actual new line character), and sets $/ to \n by default so it doesn't matter what the native OS line end convention is and it doesn't matter what character encoding is used - \n procesing using non-binary mode I/O should be portable with Perl.