Rsync

rsync

rsync (remote sync) is a fast, versatile, and widely-used command-line utility for synchronizing and transferring files and directories between two locations, either on the same system or across a network. It minimizes data transfer by only copying the differences (deltas) between source and destination files using an efficient algorithm.

Originally developed by Andrew Tridgell and Paul Mackerras, `rsync` is included by default on most Unix-like operating systems, including Linux, macOS, and BSD.

Key Features

• **Delta transfer algorithm** – Only changes within files are sent
• **Compression and encryption** – Optional `--compress` and SSH support
• **Preserves metadata** – File permissions, timestamps, ownership, symbolic links, and more
• **Supports local and remote sync** – Works on the same machine or across SSH
• **Progress and dry-run support** – Track transfers and test without making changes
• **Efficient backups** – Ideal for incremental or automated backups

Basic Syntax

 rsync [options] [source] [destination]  

Common Examples

Copy a local folder to another local directory:

 rsync -av /source/ /destination/  

Copy a folder to a remote server using SSH:

 rsync -avz /local/folder/ user@remote_host:/remote/folder/  

Sync from a remote server to local:

 rsync -avz user@remote_host:/remote/folder/ /local/folder/  

Show progress during transfer:

 rsync -avz --progress /source/ /destination/  

Dry-run (test run without actual copying):

 rsync -avz --dry-run /source/ /destination/  

Key Options

Option	Description
`-a`	Archive mode (recursive, preserve permissions, timestamps, etc.)
`-v`	Verbose output
`-z`	Compress file data during transfer
`-e ssh`	Use SSH for remote shell
`--progress`	Show progress of each file
`--delete`	Delete files in destination that no longer exist in source
`--dry-run`	Show what would be done without making changes

Use Cases

• Syncing files to a seedbox or VPS
• Backing up local or remote directories
• Deploying web content to a server
• Cloning directories with minimal data usage
• Scheduling automated backups via `cron`

rsync vs Other Tools

Feature	rsync	scp	sftp
Delta transfers	Yes	No	No
Directory sync	Yes	Partial	Partial
Compression	Yes	Yes	Yes
Metadata preservation	Full	Basic	Moderate
Interactive interface	No	No	Yes
Use over SSH	Yes	Yes	Yes

Integration with Automation

`rsync` is commonly used in automated scripts and backup systems:

• Cron jobs (`crontab -e`)
• Systemd timers
• Remote mirroring
• Snapshot backups (e.g., with hard links)

Security

• Uses SSH for encrypted transfers when specified (`-e ssh`)
• Supports public key authentication
• Minimizes attack surface by requiring only basic SSH setup

Installation

On Debian/Ubuntu:

 sudo apt update
 sudo apt install rsync

See Also

• SSH
• SFTP
• Seedbox
• Rclone