1. Introduction
What Is rsync?
rsync is a command-line tool designed for fast and efficient file and directory synchronization and copying. It is widely used on Linux and Unix-like systems, and thanks to its delta-transfer algorithm, it transfers only the differences between source and destination. This makes it highly efficient even when handling large numbers of files. On Ubuntu and many other Linux distributions, rsync is often installed by default, making it an essential tool for system administrators and developers.
Benefits of Using rsync on Ubuntu
On Ubuntu, rsync is extremely effective for daily file backups and directory synchronization tasks. Without relying on graphical interfaces, you can achieve fast file transfers—both local and remote—simply by entering a few commands in the terminal.
It is especially useful in the following situations:
- Regular backups to external HDDs or NAS devices
- Synchronizing project folders during development
- Deploying files to remote servers
- Improving availability through file mirroring
How rsync Differs from Other Commands
Compared to the cp command, rsync transfers only the differences between the source and destination, significantly reducing processing time. Compared to scp, rsync offers resume capabilities after errors and flexible bandwidth control. Additionally, it can preserve file attributes such as ownership, permissions, and timestamps, which is a major advantage.
Purpose of This Article
This article explains how to install and effectively use rsync in an Ubuntu environment, using practical command examples and real-world use cases. To ensure beginners can get started smoothly, we also cover GUI tools and troubleshooting tips while learning rsync step by step.
2. Installing rsync on Ubuntu
Checking Whether rsync Is Preinstalled
In most Ubuntu environments, rsync is already installed by default. You can check its availability with the following command:
rsync --versionIf version information is displayed, rsync is already installed and ready to use.
Installing rsync If It Is Not Installed
If you see a message such as “command not found” or “rsync: command not found,” follow these steps to install it:
- Update the package list:
sudo apt update- Install rsync:
sudo apt install rsync- Verify the installation:
rsync --versionIf version information appears, the installation was successful.
Is Installation via Snap or Other Methods Necessary?
On Ubuntu, installing rsync via APT is the most recommended approach. While Snap packages exist, the APT version is generally sufficient and offers better stability and compatibility for typical use cases. Unless you have a specific reason, APT is the preferred method.
Installation Notes
- On older Ubuntu versions, repository updates may be required.
- Root privileges are necessary, so do not forget to use
sudo. - Unstable network connections may cause installation errors; a stable connection is recommended.
3. Basic Usage of rsync
Basic rsync Syntax
The rsync command syntax is simple yet highly flexible. The basic form is:
rsync [options] source destinationFor example, to copy the contents of /home/user/documents/ to /mnt/backup/:
rsync -av /home/user/documents/ /mnt/backup/This command uses the following options:
-a: Archive mode (preserves directory structure, permissions, ownership, etc.)-v: Verbose output (shows which files are copied)
Trailing Slash Behavior
In rsync, whether you include a trailing slash in the source path changes the behavior:
/home/user/documents/(with slash)
→ Only the contents are copied./home/user/documents(without slash)
→ The directory itself is copied.
This is a critical rsync-specific behavior that should be used appropriately depending on your goal.
Commonly Used Options
| Option | Description |
|---|---|
-a | Archive mode (recursive and preserves attributes) |
-v | Displays detailed transfer output |
-n | Dry run (shows what would happen without executing) |
--progress | Shows transfer progress |
--delete | Deletes files in the destination that no longer exist in the source |
Previewing Actions Before Execution
To check what rsync will do before actually transferring files, use the --dry-run option:
rsync -av --dry-run /home/user/documents/ /mnt/backup/This helps prevent accidental data loss.
Handling Hidden Files
By default, rsync includes hidden files (those starting with .), allowing configuration files and environment settings to be synchronized as well.
4. Synchronizing with Remote Servers
Remote Synchronization via SSH
One of rsync’s biggest advantages is its ability to synchronize files with remote servers over SSH, ensuring secure data transfers.
rsync -avz source user@remote_host:destinationExample:
rsync -avz /home/user/documents/ user@example.com:/var/www/backup/-zenables compression during transfer.user@hostspecifies the SSH login.
First-Time Connection and SSH Key Authentication
On first connection, you may be asked to confirm the host authenticity. Enter “yes” if it is correct.
For frequent use, SSH key authentication is recommended to avoid entering passwords:
ssh-keygen -t rsassh-copy-id user@example.comSpecifying a Custom SSH Port
If the remote server uses a non-default SSH port, specify it with -e:
rsync -avz -e "ssh -p 2222" /home/user/documents/ user@example.com:/var/www/backup/Important Notes on Bidirectional Sync
rsync performs one-way synchronization only. For true bidirectional sync, consider tools such as unison.
5. Useful rsync Options and Practical Examples
Advanced Options Beyond the Basics
–delete: Remove Files Not Present in the Source
rsync -av --delete /home/user/source/ /mnt/backup/Always test with --dry-run before using this option.
–exclude: Exclude Specific Files or Directories
rsync -av --exclude '*.log' --exclude 'node_modules' /project/ /backup/–bwlimit: Bandwidth Limiting
rsync -av --bwlimit=5000 /data/ user@remote:/data/Real-World Use Cases
Using rsync for Backups
rsync -a --delete /home/user/ /media/usb/backup/Automating with cron
0 2 * * * rsync -a /home/user/ /mnt/backup/ >> /var/log/rsync.log 2>&1Balancing Flexibility and Efficiency
rsync combines exceptional flexibility with high transfer efficiency, making it a powerful tool for safe and precise file synchronization.
6. GUI Tool: Grsync
Recommended for Users Uncomfortable with the Command Line
Grsync is a graphical front-end for rsync that allows users to configure and execute synchronization tasks visually.
Installing Grsync on Ubuntu
sudo apt update
sudo apt install grsync
Basic Usage
- Specify source and destination paths
- Select rsync options via checkboxes
- Configure exclusion patterns
- Run dry runs safely
Profile-Based Management
Grsync allows saving configurations as profiles, making it easy to manage multiple backup or synchronization tasks.
Pros and Cons
| Pros | Cons |
|---|---|
| Intuitive GUI, no commands required | Some advanced options are not available |
| Easy to understand options | Less detailed output than terminal usage |
| Safe for beginners | Less flexible than direct rsync usage |
7. Common Problems and Solutions
File Permissions Are Not Preserved
sudo rsync -a /source/ /destination/Symbolic Links Are Not Handled as Expected
- Preserve links: use
-a - Copy actual files: use
--copy-links
“Permission denied” Errors
sudo rsync -a /source/ /destination/Connection Errors During Remote Sync
- Verify SSH connectivity
- Check destination paths and permissions
“Argument list too long” Errors
- Use include/exclude rules
- Split synchronization into smaller batches
8. FAQ
Q1. How do I preserve ownership and permissions?
A. Use the -a option.
Q2. How can I exclude specific files?
A. Use --exclude.
Q3. How do I limit bandwidth usage?
A. Use --bwlimit.
Q4. Can I preview actions before execution?
A. Use --dry-run.
Q5. Are hidden files copied?
A. Yes, by default.
Q6. What is the difference between rsync and scp?
A. rsync supports delta transfers and resume capabilities, making it more efficient.
9. Summary
This article covered rsync installation, basic and advanced usage, remote synchronization, GUI tools, troubleshooting, and FAQs.
Why rsync Is Essential
- Fast delta-based transfers
- Preserves permissions and ownership
- Secure remote synchronization
- Highly customizable with many options
- Supports automation via cron
- Beginner-friendly with GUI tools
rsync is a fundamental tool for Linux users. By mastering its basics and gradually applying advanced options, you can achieve professional-level file management and backup workflows.
