Mozilla Bookmark Merger
I needed a way to get all my bookmarks in Mozilla between a few different machines without completely over-writing files, and couldn't be bothered to work out any central-server type storage solution, so put together a small, crappy Perl script to merge bookmark files. It's very old and a bit pants and I don't know if it still works. but you can download the Mozilla bookmark merger if you want to have a look. Blah blah no license, etc. Hoping to do more work on it soon, but it's generally a matter of necessity...
Instructions? Hahahaha. Just had a look at it after 2 years, and it looks like it merges "bookmark.html" with "bookmark3.html" in the current directory. Hack the code if you want to change any of the filenames... Any URLs found in the latter will be appended to the former, showing completely disregard for folders, etc, so you'll have to re-sort the bookmarks imported from the second file. It worked for me, I think, under for Mozilla 1.6 and Firefox 0.8.
As a side-note, I'm in the process of investigating the use of CVS to handle distribution and merging of one bookmark file across several locations. Best way seems to be the above code to merge them, then go with CVS from that point on. I'll try and write this up more properly at some point.
Looks like this page shows up well on Google, plus (oddly) there's nothing else to do the job, apparently. So, maybe todo in the nearish future:
1. Sort out folder position of bookmarks properly.
2. Check for duplicates by name/URL (think it does it just be URL at the moment)
3. Maybe a slightly friendlier interface :)