Re: \c-handling in $'-strings

[Helmut Karlowski]

Am 02.09.2015, 14:19 Uhr,SCHRIEB Chet Ramey <chet.ramey@case.edu>:

> > 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

Where is that described? I could not find anything about $'...' in the  
posix-docs.

> `\c' honor backslash escaping.  Since the character becomes \c\\, the
> subsequent `c' and `]' are literals.

I assume this is only true for "to-be-escaped" characters, that is

$   `   "   \   <newline>

like for ".."-strings? Of course only \ is of interest here.

If that is true then the output of ksh93 for

echo $'\c\d' |od -a -> 0000000 eot  nl

is wrong? It removes the \ every time.

-Helmut