How to run rsync with dryrun option (–dry-run)

Rsync is a powerful tool for file synchronization, but it can potentially delete files if you’re not careful with how you use it. However, the risk of accidental file deletion can be mitigated by understanding how rsync works and using it with the appropriate options.

Here are some points to consider to prevent accidental file deletion when using rsync:

Use the –dry-run Option: Before running an rsync command that includes the –delete option, you can use the –dry-run option to simulate the synchronization and see what actions rsync would take without actually making any changes. This can help you confirm that no unintended deletions will occur.

rsync -avz --delete --dry-run source_directory/ destination_directory

Be Careful with Trailing Slashes: Trailing slashes in the source and destination paths can affect whether directories are synchronized or just their contents. Make sure you understand how these slashes work and use them appropriately.

Backup Important Data: Before performing any significant synchronization operation, especially when using the –delete option, it’s a good practice to back up your data. This way, you can restore files in case of accidental deletion.

Double-Check Paths: Ensure that the source and destination paths are specified correctly. A mistake in these paths could result in files being copied or deleted in unintended locations.

Use a Dry Run and Confirm: Even after using the –dry-run option, reviewing the output carefully is a good practice to ensure that the expected files are synchronized, and no unexpected deletions are listed.

Test with a Small Subset: When using rsync for the first time or on a new data set, consider testing with a small subset of your files to confirm that the command behaves as expected before applying it to your entire dataset.

What is dryrun (dry-run)?

A dry run is a simulation or test run of a command or operation that shows you what would happen if you were to execute it, without actually making any changes to the system. It’s often used as a safety precaution to review the potential consequences of a command before applying it to ensure that it behaves as expected.

Using a dry run can help prevent accidental data loss or unintended consequences by allowing you to catch and correct any mistakes in your command before they have real-world effects.