As you may know, Unison is an cross-platform, open-source file synchronization software that permits the users to store to copies of files and folders on two different hosts. When you want to merge the two copies, the archives get compared one with another and only the differences get copied from one replica to another.
- Unlike simple mirroring or backup utilities, 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.
- Unlike a distributed filesystem, Unison is a user-level program: there is no need to modify the kernel or to have superuser privileges on either host.
- Unison works between any pair of machines connected to the internet, communicating over either a direct socket link or tunneling over an encrypted ssh connection. It is careful with network 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.
- 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 has a clear and precise specification.
The latest version available is Unison 2.48.3, which has been recently released.
Up to date packages are available via some third party PPA, so installing the system on Ubuntu systems is easy. Just add the PPA to your system, update the local repository index and install the unison package:
$ sudo add-apt-repository ppa:eugenesan/ppa
$ sudo apt-get update
$ sudo apt-get install unison
Optional, to remove unison, do:
$ sudo apt-get remove unison
The installation instructions should work on Ubuntu 15.10 Wily Werewolf, Ubuntu 15.04 Vivid Vervet, Ubuntu 14.04 Trusty Tahr, Linux Mint 17.2 Rafaela, Linux Mint 17.1 Rebecca, Linux Mint 17 Qiana, Pinguy OS 14.04, Elementary OS 0.3 Freya, Deepin 2014, Peppermint 6, Peppermint 5, LXLE 14.04 and Linux Lite 2.