Unison is a file-synchronization tool for OSX, Unix, and Windows. It allows two replicas of a collection of files and directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to the other. Developed by Benjamin C. Pierce
License: Open Source
Beyond Compare is primarily focused on powerful file and folder comparison, offering extensive customization and integration options. In contrast, Unison is geared towards efficient bidirectional synchronization across platforms, making it better suited for users needing cross-platform file management.