https://DevOpsCloud.io -- Cloud Monk Losang Jinpa, Ph.D., MCSE/MCT, GitOps DevOps Engineer

Return to grsync, Linux commands

e.g. rsync -rtv /var/www/html/data/pages/ ~/all/coding/Web/DevopsCloud.io-Pages/data/pages/

-v means verbose

To use rsync for copying files from `/var/www/html/data/pages/` to `~/all/coding/Web/DevopsCloud.io-Pages/data/pages` without preserving symbolic links, Linux file permissions, and other Linux file attributes, but still preserving timestamps, you can use the following command:

```bash rsync -rt /var/www/html/data/pages/ ~/all/coding/Web/DevopsCloud.io-Pages/data/pages/ ```

• `-r`: This stands for recursive, which ensures that directories and their contents are copied.

• `-t`: This stands for preserve timestamps, ensuring that the modification times of files are preserved.

• Symbolic links, file permissions, Linux file ownership, and other Linux file attributes will not be preserved because you are not using the `-a` (archive) or related options.

By using `-rt`, you get a recursive copy that preserves timestamps but does not carry over symbolic links or file attributes like file permissions or file ownership.

Using rsync for efficient file synchronization: While there is no specific RFC dedicated solely to rsync, its functionality relies on network and file transfer standards outlined in various RFCs, such as RFC 959 for FTP protocols and RFC 5321 for reliable data transfer techniques. rsync is a widely used file synchronization and transfer tool that employs a delta-transfer algorithm, allowing it to detect changes between source and destination files and transfer only the altered portions of data. This makes rsync exceptionally efficient for synchronizing files across different directories, devices, or even remote servers. By reducing data transfer volume, rsync optimizes bandwidth usage, especially for incremental backups or syncing large data sets.

rsync, short for “remote sync,” is a tool designed for fast and efficient file synchronization, particularly across systems connected via a network. Built with scalability and reliability in mind, rsync supports local and remote file synchronization while minimizing data transfer times. It achieves this through an algorithm that only sends the differences between source and destination files. This delta-transfer algorithm is particularly beneficial for syncing large files where only portions of the data have changed. With a command-line interface, rsync offers flexibility in its options, enabling users to perform complex synchronization tasks with simple commands. For both system administrators and developers, rsync is valuable for tasks like backups, data mirroring, and website deployments, often functioning alongside tools that manage files over networks. Its design principles align with various standards for file transfer and reliability as described in network protocol RFCs, such as RFC 959, which underpins FTP.

The basic syntax for rsync operations follows a straightforward structure. The general command is `rsync [options] source destination`. Here, the “source” and “destination” refer to the file paths or directories involved in synchronization. The simplicity of rsync's command-line usage belies its power, as it can handle complex synchronization needs, such as recursive directory syncing, file compression during transfer, and preserving permissions, timestamps, and ownership. For example, in the command `rsync -av /source/dir/ /dest/dir/`, the `-a` option stands for “archive” mode, which enables recursive syncing and preserves file attributes, while the `-v` option increases verbosity for a more detailed output of the transfer process.

An important aspect of rsync is its ability to work over secure connections, typically utilizing the SSH protocol. By combining rsync with SSH, users can securely transfer files between remote systems, ensuring data integrity and confidentiality. When transferring files over SSH, the command syntax would include the remote server's address, such as `rsync -av -e ssh /local/dir/ user@remote:/dest/dir/`. This use of SSH aligns with security protocols outlined in various RFCs focused on encryption, providing an additional layer of security for sensitive data transfers. rsync also includes options for compression, enabled with `-z`, which reduces the amount of data transferred by compressing files during transmission. This feature is especially beneficial for transferring large files over limited bandwidth.

One of rsync's standout features is its delta-transfer algorithm, which minimizes data transfer by only sending changed portions of files. This capability is invaluable for incremental backups, where only new or modified data needs to be synchronized. By reducing the volume of data transmitted, rsync optimizes bandwidth and speeds up the transfer process. This incremental approach is similar to methodologies described in RFC 5321, which emphasizes efficiency in data exchange and error detection. Additionally, rsync's algorithm generates checksums of file chunks, allowing it to detect differences accurately. By comparing checksums between source and destination, rsync can determine which parts of a file require updating, further reducing transfer times and resource usage.

rsync is compatible with a range of operating systems, making it versatile for cross-platform data synchronization. It is especially popular on Linux and UNIX systems, where it is commonly pre-installed. Many administrators and developers rely on rsync for deploying websites, as it allows them to update files on a web server without overwriting the entire directory. This feature supports web deployment strategies by enabling incremental updates, minimizing downtime and reducing the risk of data loss. rsync's compatibility with both local and remote file paths means users can perform operations across different systems, enhancing its functionality as a synchronization tool in diverse network environments.

Error handling in rsync is robust, with detailed output provided through the `-v` and `-P` options, where `-P` enables progress reporting and partially transfers files in case of interruptions. If a file transfer is interrupted, rsync can resume the operation, thanks to its checksum-based method for verifying file integrity. This resilience is crucial in large-scale deployments where reliability is essential. Furthermore, rsync allows users to exclude specific files or directories with the `–exclude` option, making it easy to customize synchronization to meet project needs.

Automation with rsync is commonly achieved by integrating it into shell scripts or scheduling it with tools like cron. By scripting rsync commands, users can set up automated backups or regular data synchronization tasks without manual intervention. For example, a scheduled cron job can invoke rsync to perform nightly backups, ensuring data consistency and availability. rsync's flexibility in scripting and automation aligns with administrative practices for maintaining system backups and data integrity, especially in environments where data availability is critical.

rsync stands out as a powerful and versatile tool for file synchronization, offering a range of features that support secure, efficient, and customizable data transfers. By using a delta-transfer algorithm, rsync minimizes data transfer volumes and reduces network load, particularly useful in scenarios like incremental backups. With its ability to preserve file attributes, integrate with SSH for secure transfers, and support cross-platform compatibility, rsync is a valuable asset for system administrators, developers, and anyone needing reliable file synchronization. Its alignment with foundational network protocols and file transfer standards, as outlined in RFC 959 and similar documents, reinforces its reliability and efficiency as a solution for modern data management needs.

Snippet from Wikipedia: Rsync

rsync (remote sync) is a utility for transferring and synchronizing files between a computer and a storage drive and across networked computers by comparing the modification times and sizes of files. It is commonly found on Unix-like operating systems and is under the GPL-3.0-or-later license.

rsync is written in C as a single-threaded application. The rsync algorithm is a type of delta encoding, and is used for minimizing network usage. Zstandard, LZ4, or Zlib may be used for additional data compression, and SSH or stunnel can be used for security.

rsync is typically used for synchronizing files and directories between two different systems. For example, if the command rsync local-file user@remote-host:remote-file is run, rsync will use SSH to connect as user to remote-host. Once connected, it will invoke the remote host's rsync and then the two programs will determine what parts of the local file need to be transferred so that the remote file matches the local one. One application of rsync is the synchronization of software repositories on mirror sites used by package management systems.

rsync can also operate in a daemon mode (rsyncd), serving and receiving files in the native rsync protocol (using the rsync:// syntax).

Creative Commons Attribution-Share Alike 4.0