Re: Inconsistent quote and escape handling in substitution part of parameter expansions.

[Greg Wooledge]

On Tue, Feb 28, 2012 at 04:52:48PM +0100, John Kearney wrote:
> The standard work around you see is
>               echo -n \'${1//\'/\'\\\'\'}\'" "
>  but its not the same thing

Workaround for what?  Not the same thing as what?  What is this pile
of punctuation attempting to do?

> # why does this work, this list was born of frustration, I tried
> everything I could think of.
> echo \'${test//"'"/\'\\\'\'}\'" "
> 'weferfds'\''dsfsdf'

Are you trying to produce "safely usable" strings that can be fed to
eval later?  Use printf %q for that.

imadev:~$ input="ain't it * a \"pickle\"?"
imadev:~$ printf '%q\n' "$input"
ain\'t\ it\ \*\ a\ \"pickle\"\?

printf -v evalable_input %q "$input"

Or, y'know, avoid eval.

Or is this something to do with sed?  Feeding strings to sed when you
can't choose a safe delimiter?  That would involve an entirely different
solution.  It would be nice to know what the problem is.