Thanks for your help, tommyw, but it still doesn't work for me. I should have been more clear throughout my original posting that what I am searching for (and trying to replace) is a single character that is expressed as \xNN (when working in vi for instance), where NN is the hex value of the character's position in the ASCII table.

So your solution works if I'm searching for a string that looks like '\x92' but not if I'm searching for a single character (the right-single-quote character in this case) expressed as \x92.

Sorry if I wasn't clear on that before.

Thanks.