Re: Match operator puzzlement

[Byron Rakitzis <byron>]

Hm. I think I can do a little better than John here. The two following
sed substitutions should be ok to quote all characters in a word except
the metacharacters *, ? and [. The sed scripts will FAIL if there are
single quotes in the input, but I'm sure there's a way around that
problem too, I just haven't thought of a good way yet.

Anyway:

First you turn all single non-meta characters into quoted characters:
	
	sed 's/\([^[*?]\)/''\1''/g'	# using rc's quoting rules, of course.

e.g., "Hello?" goes to "'H''e''l''l''o'?"

Now you need to remove all '' sequences:

	sed 's/''''//g'

Now "Hello?" becomes "'Hello'?", which is exactly what we want. Not bad.

(BTW, I think I can prove by induction that this method works for all
strings which do not contain a ', but I do not have enough room
to write the proof here :-)

So the ~ example becomes something like:

	eval ~ 'subject' `{echo $funky_pattern | sed garbage}