I have about 100 bookmark files: that is, .html files containing bookmark lists. Each file contains several hundred bookmarks, and there is probably about a 90% duplication from file to file. Unfortunately, the bookmark structure within each file is not always the same.

Anyway, I need to boil them down to a single bookmarks.html file. I am willing to spend some time to do this, but I can't go through what amounts to probably 20,000 individual bookmarks looking for duplicates. It has to be an at-least-semi-automated process.

If I could find a program/app that could just compare two files at a time, remove duplicate bookmarks, and save the result, I'd be happy. Freeware would be great but I am willing to pay if there's a program that really does what I want and does it well.

FWIW, my main browser is Chrome but I also use Firefox and Opera on occasion. The software that created these bookmark files was xmarks (which I do not recommend.)