This comes straight from the camel's mouth (page 685, para 1):

binmode
  binmode FILEHANDLE, DISCIPLINES
  binmode FILEHANDLE

This function arranges for the FILEHANDLE to have the semantics
specified by the DISCIPLINES argument. If DISCIPLINES is omitted,
binary (or "raw") semantics are applied to the filehandle.
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TStanley
In the end, there can be only one!