Not OP, but this is my script: https://gist.github.com/smj-edison/33229537007a73520a26a14a0...

It's been cobbled together over the years to add things I want, like not backing up on battery, or sending a desktop message on success. When I set it up I couldn't figure out how to set up a timer, so it runs when I wake from suspend. I'd probably use a systemd timer in the future though.

I also should probably snapshot my file system before backing up since I'm running btrfs, but I never figured out how to do that either, and this works, lol.