bmdiff.pl (a contraction of "bookmark diff") is a short Perl script to compare versions of a Netscape/Mozilla/Firefox bookmarks file (bookmarks.html). It can report links that have been added, removed, and preserved, and identify duplicates (even if they have different labels and/or locations in the bookmarks file).

The script outputs HTML to stdout, redirect to a convenient file and open in your browser. Each bookmark presented as a link, which can be bookmarked in the normal manner. Here's an example of the output.

Usage:
bmdiff -[arpdl] oldfile newfile > output.html

The following flags are permitted:

a		Show added links.
r		Show removed links.
p		Show preserved links.
d		Show duplicate links.
l		Long format, includes bookmark locations.

If no flags are specified, -ard is assumed.