shebang strange thing...

Kim Petersen kp at kyborg.dk
Sat Jun 28 00:28:13 CEST 2003


Ben Finney wrote:
> On Fri, 27 Jun 2003 10:46:49 +0100, Tim Rowe wrote:
> 
>>On 27 Jun 2003 09:33:23 +0950, Ben Finney wrote:
>>
>>>So, it was teletypes that needlessly preserved the CR and LF as
>>>separate control operations
>>
>>It wasn't needless.  A CR with no LF  was often used for overstriking,
>>as a way of extending the rather limited character set.  'O'
>>overstruck with '-' would make a passable \Theta, for instance..
> 
> 
> Overstriking is amply catered for with the BS (BackSpace) control code.
> For the "theta" example:  emit a 'O', emit a BS, emit a '-'.  In fact,
> this method continues today in some *roff outputs, for bold or digraph
> characters.  The CR is completely redundant for this purpose.

Although the first is correct (using BS to get the effect) it implies 
that the printer/typewriter that you want to make this effect on, is 
able to backspace _precicely_ whereas the CR method can be made simple 
and easy with a mechanical(?) stopper, that ensures that you always 
start at the same point.

> 
> I maintain that the CR and LF were needlessly preserved as separate
> operations, with no benefit.
> 


-- 
Med Venlig Hilsen / Regards

Kim Petersen - Kyborg A/S (Udvikling)
IT - Innovationshuset
Havneparken 2
7100 Vejle
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