I have implemented a new feature on my (relatively) old hexeditor HyperEdit.
The new feature is a search function that allows approximate matches.
If the user searches for "cprogrammign" in the text "This is a c-programming forum" the program still finds the string, even though one '-' is missing and two characters has switched places.
If you're interested, download the program here: HyperEdit (815kB)
The tolerance is given in %. If the tolerance is set to 80% and the word is 5 characters long, no more than .20*5=1 differences may be present to render a match. Thus, a tolerance of 100% requires a perfect match.
I'd like this function to be tested, but you are always welcome to submit bugs on other functions as well.
(Edit) BTW, Do you know of any hexeditor/word processor that has a similar function, I can't seem to find one in, for example, Word.