Not sure what you mean? Dumper doesn't AFAIK have interpretations of CR LF, it is just showing the data, either outputting it raw (for the CRLF-relevant characters) or as escapes with Useqq, where \r means chr(0x13) and \n means chr(0x10) (assuming non-EBCDIC). If perl is opening the source in text mode, a binmode *DATA; before the seek/read may be good (don't know if that even works or if *DATA is somehow magic in a way that prevents changing layers).