Unison is a file synchronization tool for Windows and various Unix-like systems (including macOS and Linux).

Unison allows synchronization via computer networks (LAN, Internet) by direct connection (socket) or tunneled via ssh.

Unison can be called via the command line with parameters or controlled via profile files.

Afterwards Unison creates a replication list with suggestions for their synchronization and marks conflicts that cannot be resolved automatically.

Compared to rsync, Unison is fully bi-directional and allows the user to detect and reconcile conflicts when both copies of a file have been changed since the last synchronization.