rsync
rsync is a fast, versatile file synchronisation and transfer tool that copies files locally or over a network using an efficient delta-transfer algorithm. It transfers only the differences between source and destination files, minimising bandwidth usage and transfer time. rsync is the backbone of countless backup systems, mirroring setups, and deployment pipelines, and is pre-installed on virtually every Linux and macOS system.
Key Features
- Delta transfer — Only transfers differences between files, not entire files
- Compression — Optional on-the-fly compression for faster transfers over slow links
- Preservation — Preserves permissions, ownership, timestamps, symlinks, and ACLs
- Remote shell support — Works over SSH by default for encrypted transfers
- Daemon mode — Run as a service for anonymous or authenticated rsync access
- Bandwidth limiting — Throttle transfer speed with the –bwlimit option
- Dry-run mode — Preview what would be transferred without actually copying
- Exclude patterns — Exclude files and directories with flexible pattern matching
Why Use It
rsync is the most efficient file transfer tool available for bulk data. Its delta-transfer algorithm means repeated backups of large files take seconds instead of minutes. Combined with SSH, it provides encrypted, authenticated transfers that work through firewalls.
Use Cases
- Automated backups — Incremental backups with minimal bandwidth usage
- Server mirroring — Keep multiple servers synchronised across data centres
- Deployment — Push application code and configuration to production servers
- Migration — Transfer large datasets between storage systems
Platform
Linux, macOS, BSD, Windows (via WSL or Cygwin)
Licence
GNU General Public License v3.0