unison
SHA-256Unison is a cross-platform file-synchronization tool for POSIX systems and Windows, supporting bidirectional updates, conflict detection, and efficient communication over SSH or TCP.
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v2.54.0 · 3.6 MB
Bidirectional file sync tool that works across platforms without admin rights, handling conflicts automatically.
Core Features
- Cross-platform (Windows, macOS, Linux, *BSD)
- Bidirectional sync: merges changes on both sides, auto-propagates non-conflicting updates, and highlights conflicts
- User-level program: no kernel modules or superuser needed
- Communication via SSH or TCP with bandwidth optimization (rsync-like compression)
- Crash-resistant: leaves replicas and private structures in a consistent state
What It Can't Do
- •Warning: Unison versions are NOT cross-compatible; use the same version on all machines. Old versions (2.48, 2.51) are unsupported; use the latest from git/master. When both sides modify the same file, manual conflict resolution is required. The project has very limited maintainers (~2.5 people), so bug fixes and new features may be slow.
Use Cases
- Synchronize files between a laptop and a desktop/server
- Offline-capable backup and restore
- Keep project files consistent across multiple machines
- Bi-directional sync for remote team collaboration
Unison is a file-synchronization tool for POSIX-compliant systems (e.g., *BSD, GNU/Linux, macOS) and Windows. It enables two replicas of a collection of files and directories to be stored on different hosts or disks, modified separately, and then brought up to date by propagating changes in each replica to the other. Key features include cross-platform support, bidirectional synchronization handling updates on both sides, automatic propagation of non-conflicting changes, and clear detection of conflicting updates. It operates as a user-level program without kernel modifications or superuser privileges, communicates over SSH or TCP, uses a compression protocol similar to rsync for small updates to large files, and is resilient to failures. Unison can run in repeat mode with a filesystem monitor for near-real-time synchronization. It has been in use for over 25 years and is provided under the GPLv3 license.
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Getting Started
Download installer
Click the button above to download the installer for your system
Install the software
Open the downloaded dmg file, then drag the app to Applications
Step 1: Install Unison via package manager (e.g., Ubuntu: `sudo apt install unison`; macOS: `brew install unison`; Windows: download from GitHub releases)
Step 2: Create a profile file (e.g., `~/.unison/default.prf`) specifying local/remote directories and connection method
Step 3: Run `unison` to start sync; on first run, review and resolve any conflicts
- Step 1: Install Unison via package manager (e.g., Ubuntu: `sudo apt install unison`; macOS: `brew install unison`; Windows: download from GitHub releases)
- Step 2: Create a profile file (e.g., `~/.unison/default.prf`) specifying local/remote directories and connection method
- Step 3: Run `unison` to start sync; on first run, review and resolve any conflicts
SHA-256 checksum verified
Checksum extracted from GitHub official Release page
SHA256 Checksum
8e0c9070824dc7e3f207d54c8afdec1af55ac26af2740d0d5d7b6e00c44d5fabThis checksum is extracted from the GitHub Release page. Verify file integrity after download.
All SHA-256 checksums on this platform are extracted from the project's official GitHub Release page, without any modification. You can independently verify them on the GitHub Releases page.
Open Source Transparency
View GitHub SourceUninstall Info
Remove using your package manager (e.g., `sudo apt remove unison`) or delete the application manually.
No Extra Dependencies
Ready to use after download. No additional runtime required.
Having issues? Check the FAQ below
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