Projects / Unison


Unison is a file-synchronization tool for Unix and Windows. It allows two copies 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. Unison can deal with updates to both replicas of a distributed directory structure. Updates that do not conflict are propagated automatically. Conflicting updates are detected and displayed. Unison can communicate through a direct socket link or through an rsh/ssh tunnel. It uses network bandwidth efficiently.

Operating Systems

RSS Recent releases

  •  14 Mar 2008 01:44

No changes have been submitted for this release.

  •  15 Mar 2006 11:20

Release Notes: A new convention for release numbering: releases will continue to be given numbers of the form X.Y.Z, but from now on, just the major version number (X.Y) will be considered significant when checking compatibility between client and server versions. There is a warning (failure in batch mode) when one path is completely emptied. This prevents Unison from deleting everything on one replica when the other disappears. A diff bug where no difference was shown the first time the diff command was given has been fixed. There are user interface improvements.

  •  15 Mar 2006 11:17

    Release Notes: The archive format has changed. Major tidying and enhancement of the 'merge' functionality. Files larger than 2 Gb are now supported. This release adds preliminary (and still somewhat experimental) support for the Apple OS X operating system.

    •  17 Apr 2002 12:16

    Release Notes: Major enhancements include a multi-threaded file transport module, which can result in 5-10x improvements in transfer speeds. The "hanging transfer" bug in 2.8.1 has been fixed, along with some subtle but potentially serious bugs in the synchronization logic.

    •  16 Sep 2001 12:21

    Release Notes: Fixes for a bug in 2.7.4 that prevented the client from establishing a connection with the server, and a bug in 2.7.1 that hung instead of giving a correct diagnostic when used with an incompatible server. These bugs affect only installation.

    RSS Recent comments

    05 Jan 2011 01:42 bcrowell Thumbs up

    Loveitloveitloveit! Unison has been one of my crucial tools for years now. The recent versions are extremely solid.

    07 Feb 2005 12:23 floyd59 Thumbs up

    Excellent file synchronizer
    This tool was written by the guys at CERN, the european particle physics laboratry. Obviously they know what they are doing, this software performs simply without flaw.

    18 Oct 2004 09:31 mela Thumbs up

    Extremly useful
    If you have to share data between two or more

    computers, and want to keep it it _in sync_ you can't step

    over unison.

    I'm using it now for over a year to sync data between my

    notebook and my Workplace-PC and it grows to one of my

    most important tools. in one row with ssh, a mailreader,

    vi and bash itself...

    Keep up the good work!


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