finding similar files

[Hendrik Boom <hendrik@topoi.pooq.com>]

There wouldn't happen to be any handy tools for searching a directory 
tree with a few hundred ASCII files and telling me which ones have 
similar content?

Many have been copied, edited, merged, reformatted, split, and I'd like
to find the differences, decide on what to keep, and delete redundant
ones.

I know there's such a program for image files.

I know about wdiff, which would be fine after I've paired off the similar 
files (or fragments of files). to resolve differences that remain.

What I'm looking for is something that will give me a first cut on 
finding those pairs of files.

-- hendrik