You should probably take a look at the rsync-related tools: rdiff and rdiff-backup.

You should probably take a look at the rsync-related tools: rdiff and rdiff-backup. The rdiff command lets you produce a patch file and apply it to some other file.

The rdiff-backup command uses this approach to deal with entire directories, but I'm guessing you're working with single-file disk images, so rdiff will be the one to use.