Search:

Hmm, sounds like you're trying to do everything at the same time.

A better way might be to read in all the titles first, remove all duplicates, and then write out to the file.

If you have a lot...

I can't think of any nice way to handle this other than don't do it.

You should be able to modify elements safely (assuming you synchronize properly), but if you're adding/removing elements you'll...