Overview
rsync is highly efficient for synchronizing large files or a large number of files by using a 'delta-transfer' method that transfers only the changed parts of files. It can transfer files between local file systems, from local to remote, and from remote to local.
Key Features
- Delta transfer (transfers only changed parts)
- Supports local and remote synchronization
- Preserves metadata such as permissions, ownership, and timestamps
- Compressed transfer and bandwidth control
- Specifies file exclusion/inclusion patterns
Common Options
rsync offers a wide range of options, but here are some of the most commonly used ones.
Basic Operations and Archive
Transfer Control
Network
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Usage Examples
Examples demonstrating various usage scenarios of rsync.
Synchronize Local Directories (Most Common)
rsync -avz /path/to/source/ /path/to/destination/Copies/synchronizes the contents of the source directory to the destination directory. The combination of -a (archive), -v (verbose), and -z (compress) options is most frequently used.
Push Files to a Remote Server
rsync -avz /path/to/local_source/ user@remote_host:/path/to/remote_destination/Synchronizes the local source directory to the destination directory on a remote server.
Pull Files from a Remote Server
rsync -avz user@remote_host:/path/to/remote_source/ /path/to/local_destination/Synchronizes the source directory on a remote server to the destination directory locally.
Mirroring Source and Destination (--delete Option)
rsync -avz --delete /path/to/source/ /path/to/destination/Ensures the source directory and destination are exactly identical. Files not present in the source will be deleted from the destination. It is strongly recommended to test with `--dry-run` first.
Exclude Specific Files/Directories
rsync -avz --exclude='*.log' --exclude='temp/' /path/to/source/ /path/to/destination/Excludes log files and the 'temp' directory from synchronization.
Simulate Before Execution (--dry-run)
rsync -avz --delete --dry-run /path/to/source/ /path/to/destination/Shows what rsync will do without actually changing files. This is essential, especially before using options like `--delete`.
Installation
rsync is installed by default on most Linux distributions. If it is not installed, you can install it using the following commands.
Debian/Ubuntu
sudo apt update
sudo apt install rsyncCentOS/RHEL/Fedora
sudo yum install rsyncArch Linux
sudo pacman -S rsyncTips & Precautions
Tips and precautions for using rsync more effectively and safely.
Importance of the Trailing Slash (/) in Paths
The behavior changes depending on whether a trailing slash is present in the source path.
- `/path/to/source/` (with slash): Copies the 'contents' of the `source` directory to the destination.
- `/path/to/source` (without slash): Copies the `source` directory 'itself' to the destination. (The `source` directory will be created inside the destination directory)
Utilizing the --dry-run Option
Especially when using destructive options like `--delete`, always test with `--dry-run` first to prevent unexpected data loss.
Permissions and Ownership Issues
The `--archive` option attempts to preserve permissions and ownership, but issues may arise if the corresponding user/group does not exist on the destination system or if permissions are insufficient. In such cases, consider using `sudo` or options like `--no-p` (do not preserve permissions), `--no-o` (do not preserve owner), `--no-g` (do not preserve group).
Bandwidth Limiting
To avoid excessive network bandwidth usage, you can limit the transfer speed using the `--bwlimit=KBPS` option. (e.g., `--bwlimit=1000` limits to 1MB/s)