Re: Special control characters ???

[Elizabeth Barham <lizzy@soggytrousers.net>]

Michael writes:

> First, two examples:
> 
>    ^I
>    ^M
> 
> Obviously, you know that these are each single characters, and not two:
> caret+letter.
> 
> Where do these come from?  Are they features of the shell?

They're simply adjustments to the output for the rendering of
non-visual ASCII characters for the sake of the person sitting behind
the console. They're features of the terminal; see stty(5),
specifically:

       * [-]ctlecho
              echo control characters in hat notation (`^c')

> Where is an exhaustive list of such special control characters, and
> their definitions?

$ apt-get install ascii
$ ascii

for starters although if you're extremely interested in this you may
want to investigate the origins of encoding standards used in early
serial communications.

         http://www.staubassociates.com/dbase/bu07sh.htm

> They come in quite handy for shell scripts, and I'm sure there are
> those about which I do not know, that can make life easier.
> 
> What do you think?

It has its place.

Elizabeth