ss3b is a simple backup system I put together to make incemental backups sane for me. You can read more about it on github, but effectively it makes use of incremental features of tar, some encrpytion, the AWS CLI tool, and some bash. You feed it a config and a list of directories to routinely back up, drop it in a crontab, and forget about it.
There are quite a few systems out there, but my goal was to use as many "default" system tools as possible. It does use a bit of bash specific code, but hey... it's bash.