Re: \c-handling in $'-strings

[Chet Ramey]

On 9/1/15 6:46 PM, Helmut Karlowski wrote:

> Do you refer to the table titled "Circumflex Control Characters in stty"?
> 
> It states for example:
> 
> ?    <DEL>

Yeah, that's a problem.  I've fixed that.

> 
> Running:
> 
> echo $'\c?' |od -a
> echo $'\c[\c\\c]\c^\c_\c?' |od -a
> 
> bash prints:
> 
> 0000000  us  nl
> 0000002
> 0000000 esc  fs   c   ]  rs  us  us  nl
> 
> I'd expect:
> 
> 0000000 del  nl
> 0000002
> 0000000 esc  fs  gs  rs  us del  nl
> 
> Also the ] in the output seems wrong, looks it gets the \\ wrong, though
> ksh93 does this also.

The Posix standardization of $'...' requires that the character after the
`\c' honor backslash escaping.  Since the character becomes \c\\, the
subsequent `c' and `]' are literals.

Chet

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/