Back In Time back from the dead
Back In Time is a GPL-2.0-licensed backup tool based on rsync and written in Python. It has both graphical and command-line interfaces, and supports backups to local disks or over SSH. Back In Time was originally written by Oprea Dan and released in 2009. The tool has been through some rough patches over the years, and is currently on its third set of maintainers. Christian Buhtz, one of the current maintainers, explained to me how he and his co-maintainers had revived the project, as well as why he thought Back In Time stood out from all of the existing backup solutions.
The tool
On first starting up, Back In Time offers to restore a previous configuration from an existing backup on another computer — a nice touch, since it means that restoring backups onto a new computer is as simple as starting the tool and pointing it at the right location. If one does not have an existing configuration, the tool prompts for the information needed to create a new profile. This includes all of the normal options that backup software offers — local and remote backups, encryption, folders to include and exclude, number of backups to keep, etc. — but it also includes some features that are less common, such as the ability to run a backup whenever a particular hard drive is connected. It's also possible, under "Expert Options", to change the priority given to the backup process, to restrict how much network bandwidth it uses, and so on. Despite its other features, Back In Time does not support backing up to cloud storage, or via any protocol other than SSH.
Once configured, Back In Time will (by default) automatically add itself to the user's crontab file, to run backups at the specified frequency. If the user disables crontab-handling, they can instead run Back In Time's command-line tool by some other means. Users who spend all their time in the terminal can avoid the GUI entirely by writing their own configuration to ~/.config/backintime/config, although the project's documentation doesn't really cover that case.