Unison File Synchronizer
Meta
Please read this entire README and
https://github.com/bcpierce00/unison/wiki/Reporting-Bugs-and-Feature-Requests
before 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 read https://github.com/bcpierce00/unison/wiki before
interacting with the issue tracker or asking for help.
About
Unison is a file-synchronization tool for POSIX-compliant systems
(e.g. *BSD, GNU/Linux, macOS) 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.
Unison has been in use for over 25 years and many people use it to
synchronize data they care about.
Features:
-
Unison works across platforms, allowing you to synchronize a
Windows laptop with a Unix server, for example.
-
Unlike simple mirroring or backup utilities, Unison can deal with
updates to both replicas of a distributed directory
structure. Updates that do not conflict can be propagated
automatically. Conflicting updates are detected and displayed.
-
Unlike many network filesystems, Unison copies data so that
already-synchronized data can be read and written while offline.
-
Unlike most distributed filesystems, Unison is a user-level program
that simply uses normal systems calls: there is no need to modify
the kernel, to have superuser privileges on either host, or to have
a FUSE implementation.
-
Unison works between any pair of machines connected to the
internet, typically communicating over ssh, but also directly over
TCP. It is careful with network bandwidth, and runs well over slow
links. Transfers of small updates to large files are optimized using
a compression protocol similar to rsync.
-
Unison is resilient to failure. It is careful 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.
-
Unison can run in "repeat" mode with a filesystem monitor, so that
changes are synchronized soon after they happen.
-
Unison has a clear and precise specification.
-
Unison is Free; full source code is available under the GNU Public
License, Version 3.
Contributing
Note that only a very small number of people are actively working on
maintaining unison. An estimate is 2.5 people and 0.1 Full-Time
Equivalents. This has a substantial impact on the handling of bug
reports and enhancement reports. Help in terms of high-quality bug
reports, fixes, and proposed changes is very welcome. Help in
answering mailinglist questions is also welcome. Please do not answer
questions asked in the bug tracker, which is contrary to bug tracker
usage guidance.
See CONTRIBUTING.md for a longer discussion.
Community
Unison activity is now centered on the two Unison
mailinglists
for discussion and Unison's github
page for code, issues and a
wiki.
The unison-users@ list is appropriate for asking for help. The
unison-hackers@ list is appropriate for discussions where
participants might be reading source code in order to inform the
discussion.
A no-longer-maintained FAQ can be found at: the old UPenn
site.
Getting Unison
The Unison project provides Unison as source code. Many packaging
systems (including GNU/Linux distributions) provide binary packages of
Unison. Results from Continuous Integration builds, while performed
for the purposes of testing, are available for use on a limited set of
platforms.
See the top-level wiki
page for a variety of
information, including how to access Unison documentation.
See the building instructions, or read the CI
recipes.
You should use the most recent formal release, or a newer version from
git. Earlier versions are no longer maintained, and bug reports are
not accepted about these versions. This is true even though many
packaging systems (including GNU/Linux distributions) continue to have
2.51 or even 2.48. The master branch in git historically has been
quite stable.
/unison