This is strangely written. NL is not a character. It is an operation. Every time he writes "NL character" he means an LF, i.e. 0x0A.
The NL operation is defined differently for different OSs. Yes, CRLF is a relic of the teletype, but in practice, it's really the Windows convention inherited from DOS. L/unix has always been LF. On old Mac operating systems it was CR alone.
The NL operation is defined differently for different OSs. Yes, CRLF is a relic of the teletype, but in practice, it's really the Windows convention inherited from DOS. L/unix has always been LF. On old Mac operating systems it was CR alone.