In windows (and other CRLF platforms), not only can $/ be changed, but the meaning of \n can too.

There are two types of input streams, on windows... Text, and binary (ftp suffers from this atrocity too...).

if you open a file it's normally considered a text file, and printing "\n" into it will result in a CRLF. However, if you binmode FILEHANDLE, then printing "\n" will result in LF, and "\r" will result in CR.

Scary, huh?