>Linefeed (\n) is a single byte in DOS as well.

In binary mode. In text mode if you printf(“Hello World\n”) you get CRLF because that’s how text works on DOS. Unix had the convention of only requiring the LF for text. And Unix didn’t have text/binary modes. That’s the compatibility hack on DOS.

>These control codes go back to line printers.

Back to teletypes even. Believe me, I go back to line printers.