> Is there a single character (^%NL%) that includes both?
Yes the \R. It summarizes all legal line ends but does NOT work in
> If both are required to form a new line, then why
> does their order matter?
This is not a list of possible characters, like a class in square
brackets, but a phrase that has to occur in that precise form, just like
http or anything else. In all systems related to DOS the two character
sequence \r\n constitutes a line end. The historical reason is that in
teletypes a carriage return (to the left edge) and a line feed are two
distinct mechanical processes and that they take time. Unless you
allowed for that time by sending two characters instead of just one the
next printable one would have been lost.