There's a long section on this is the perlport manpage (perl portability).

The "\n" is just a representation of an actual bit pattern, and that bit pattern my be different from system to system. It's a "logical newline", so it ends up being what that system needs as a newline.

Some things that really care about the bit patterns (such as protocol modules) sometimes specify the exact bit sequence they want instead of relying on a logical representation.

# from CGI.pm

$EBCDIC = "\t" ne "\011";
if ($OS eq 'VMS') {
  $CRLF = "\n";
} elsif ($EBCDIC) {
  $CRLF= "\r\n";
} else {
  $CRLF = "\015\012";
}
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As for annotating the end of your problem, you could post a thank you with a summary of which answers helped you figure out the solution (or even which didn't). :)