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File synchronizer

Unison is a multi-platform file-synchronization tool. It stores two replicas of a collection of files and directories on different hosts (or different disks on the same host), can modify them separately, and then updates them by propagating the changes in each replica to the other. NON-conflicting updates are propagated automatically; conflicting updates are detected and displayed. Unison can deal with updates to both replicas of a distributed directory structure. It works across platforms, and is a user-level program- users do not need superuser privileges on either host. It works between any pair of machines connected to the internet, communicating over either a direct socket link or tunneling over an rsh or an encrypted ssh connection. It conserves bandwidth, and runs well over slow links such as PPP connections. Transfers of small updates to large files are optimized using a compression protocol similar to rsync.


User manual available in HTML format from http://www.cis.upenn.edu/~bcpierce/unison/download/stable/latest/unison-manual.html

Related Projects



Verified by

Verified on


Verified by

Janet Casey

Verified on

17 July 2003

Leaders and contributors

Benjamin Pierce Maintainer
Matthieu Goulay Contributor
Sylvain Gommier Contributor

Resources and communication

AudienceResource typeURI
DeveloperVCS Repository Webviewhttp://www.cis.upenn.edu/~bcpierce/unison/svn-instructions.html
Bug Tracking,SupportE-mailmailto:unison-users@groups.yahoo.com
Debian (Ref)https://tracker.debian.org/pkg/unison
Python (Ref)https://pypi.org/project/unison

Software prerequisites

This entry (in part or in whole) was last reviewed on 18 April 2018.


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