In Windows, if you don't use binmode then "\r\n" in a file will become "\n" when the file is read.

I started writing a patch for open.pm to make binmode work with <> and @ARGV, but the related Perl source code makes this hard to do and I'd fix the code by fixing <> to not be magical by default (so that having a file named "rm -rf ..|" was no longer a horrible security problem with Unix Perl) but p5p wants that to remain a horrible security problem so I gave up on it (note that their choice also makes the patch much harder to implement so my reasons for abandoning the project were more than just a moral stance).