'#' as comment character vs. '#' as erase character

[Doug Gwyn <gwyn>]

> >	2) Why were the '#' and '@' characters used as editing characters,
> >	   other than nostalgia for Multics (which used lots of weird IBM
> >	   2741 printing terminals over half-duplex lines, and couldn't
> >	   do much better)...
> 
The older UNIXes in cooked mode would echo everything one typed,
including control characters.  About the only safe characters to
use for "magic" things were printable characters such as \ # @.
This works out better on hardcopy terminals, too, which is what
most of the original UNIX terminals were.