My issue is that I need to periodically synchronise a couple of directories on machines which are on different networks. The way I've solved it is to zip the whole thing on one machine, pass that zip file over the internet, then synchronise from that to the second machine (and if necessary, pass the zip file back to the first machine and synchronise again there).
This works, but the problem is that I'm up/downloading a 250MB file each time to synchronise maybe 10 or 15 files buried in the subdirectories. What I really need is to do the comparison and then extract *only the different files*, so these can be zipped into a couple of MB instead. Crucially, I would still need to preserve the complete paths to the various subdirectories so it's easy to paste them at the other end.
I feel like there must be some trick to do this, but I'm not really sure how...
Hmm... after writing this I have a feeling it would be something like making a copy of the big zip file, filtering on the "=" files and deleting them, leaving all the different ones. I will go do some testing!
