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Please read this entire README andhttps://github.com/bcpierce00/unison/wiki/Reporting-Bugs-and-Feature-Requestsbefore creating or commenting on a github issue.

TL;DR: Do not ask questions or ask for help in issues. Upgrade to the latest release.

Please also readhttps://github.com/bcpierce00/unison/wiki beforeinteracting with the issue tracker or asking for help.

Unison is a file-synchronization tool for POSIX-compliant systems(e.g. *BSD, GNU/Linux, macOS) and Windows. It allows two replicas of acollection of files and directories to be stored on different hosts(or different disks on the same host), modified separately, and thenbrought up to date by propagating the changes in each replica to theother.

Unison has been in use for over 20 years and many people use it tosynchronize data they care about.

Features:

• Unison works across platforms, allowing you to synchronize aWindows laptop with a Unix server, for example.

• Unlike simple mirroring or backup utilities, Unison can deal withupdates to both replicas of a distributed directorystructure. Updates that do not conflict can be propagatedautomatically. Conflicting updates are detected and displayed.

• Unlike many network filesystems, Unison copies data so thatalready-synchronized data can be read and written while offline.

• Unlike most distributed filesystems, Unison is a user-level programthat simply uses normal systems calls: there is no need to modifythe kernel, to have superuser privileges on either host, or to havea FUSE implementation.

• Unison works between any pair of machines connected to theinternet, typically communicating over ssh, but also directly overTCP. It is careful with network bandwidth, and runs well over slowlinks. Transfers of small updates to large files are optimized usinga compression protocol similar to rsync.

• Unison is resilient to failure. It is careful to leave the replicasand its own private structures in a sensible state at all times,even in case of abnormal termination or communication failures.

• Unison can run in "repeat" mode with a filesystem monitor, so thatchanges are synchronized soon after they happen.

• Unison has a clear and precise specification.

• Unison is Free; full source code is available under the GNU PublicLicense, Version 3.

Note that only a very small number of people are actively working onmaintaining unison. An estimate is 2.5 people and 0.1 Full-TimeEquivalents. This has a substantial impact on the handling of bugreports and enhancement reports. Help in terms of high-quality bugreports, fixes, and proposed changes is very welcome. Help inanswering mailinglist questions is also welcome. Please do not answerquestions asked in the bug tracker, which is contrary to bug trackerusage guidance.

SeeCONTRIBUTING.md for a longer discussion.

Unison activity is now centered on the twoUnisonmailinglistsfor discussion andUnison's githubpage for code, issues and awiki.

Theunison-users@ list is appropriate for asking for help. Theunison-hackers@ list is appropriate for discussions whereparticipants might be reading source code in order to inform thediscussion.

A no-longer-maintained FAQ can be found at: theold UPennsite.

The Unison project provides Unison as source code. Many packagingsystems (including GNU/Linux distributions) provide binary packages ofUnison. Results from Continuous Integration builds, while performedfor the purposes of testing, are available for use on a limited set ofplatforms.

See thetop-level wikipage for a variety ofinformation, including how to access Unison documentation.

See thebuilding instructions, or read the CIrecipes.

You should use the most recent formal release, or a newer version fromgit. Earlier versions are no longer maintained, and bug reports arenot accepted about these versions. This is true even though manypackaging systems (including GNU/Linux distributions) continue to have2.51 or even 2.48. The master branch in git historically has beenquite stable.