I have a folder with one big file. This is a file that changes each day. Using tar for incremental backups is not a good idea as that big file (each file that is changed is saved) will be copied each day that an incremental backup is made.
Is there an application that makes a diff of two binary files (a differential backup)?
Thanks.
Look into duplicity as a way to do incremental backups.
rsync will make a full backup, but by copying only changes (if you don't care so much for storage space, its I/O that matters to you).
Alternatively, there's rdiff or xdelta that will work for binary files, your mileage may vary depending on where the changes occur inside the binary file to result in efficient changes or not. XDelta should work well for you though.
I found bsdiff here but I have never tried it and according to the developer it's a very memory hungry app...
Hope it helps you and let me know how it works out for you.