Unison

Summary: Unison is a file-synchronization tool that enables users to maintain two replicas of a collection of files and directories on different hosts or disks. This tool allows for the synchronization of updates between the two replicas, automatically propagating non-conflicting changes while detecting and displaying conflicting updates. Unison runs across platforms, including Windows, Unix, and macOS, making it an ideal solution for users who need to synchronize data between devices running different operating systems.

Main Features:

• Cross-platform compatibility: Unison works seamlessly across Windows, Unix, and macOS platforms.
• Bi-directional synchronization: Unison can deal with updates to both replicas of a distributed directory structure, automatically propagating non-conflicting changes while detecting and displaying conflicting updates.
• Offline access: Unison copies data so that already-synchronized data can be read and written while offline.
• Resilience to failure: Unison is designed to leave the replicas and its own private structures in a sensible state at all times, even in case of abnormal termination or communication failures.
• Optimized compression protocol: Transfers of small updates to large files are optimized using a compression protocol similar to rsync.
• Repeat mode: Unison can run in "repeat" mode with a filesystem monitor, synchronizing changes soon after they happen.
• Open-source and free: Unison is open-source software available under the GNU Public License, Version 3.