Seconding unison. It's kind of a forgotten tool but it's remarkably robust and good at what it does. (I have to think being written in OCaml has been part of why it doesn't have more of a community around it.)

When I checked a few years ago, unison worked but was (a) relatively slow, and (b) very picky about which versions are at which end.

almost any two rsyncs from the last 20 years speak to each other and do it rather quickly.

For picky versions, there is nice `addversionno = true` option, which will let you have multiple unison versions installed simultaneously. It will always pick the right one.

I agree with slowness -- I feel the recent versions are pretty fast on Linux, but it can be faster. Also it's "scan, then transfer" approach means it can take lots of memory if there is a lot of files.

Still, if you can your rsync in your application, use it. For automated backups, you cannot beat it. But unison has two unique advantages:

- Proper two way sync -- doing it safely with rsync is almost impossible.

- GUI/TUI which shows what changed and allows conflict resolution.

- GUI which shows

Indeed. But you still need multiple versions installed, which means you have to sidestep package managers (and generally common usage practices); which is really inconvenient if you have multiple systems with different os’s and distros.

Also, syncthing. It seems to be better maintained. It does not preserve special file attributes and symlinks, though.

I had never come across that one either, thanks for the link! It does look a little on the heavy side for my use case, but it might come in handy at some point! It looks like it has all the bells and whistles. Cheers.