## TL;DR

rsync is a fast file synchronization tool using delta-transfer algorithm — only transfers differences between source and destination. `rsync -avz source/ user@host:/dest/`. Ideal for backups, mirroring, deployment. Bandwidth-efficient: only changed blocks, not entire files.

## Core Explanation

Flags: `-a` (archive mode = preserve permissions/ownership/timestamps), `-v` (verbose), `-z` (compress), `-P` (progress + partial), `--delete` (remove dest files not in source). Dry-run: `--dry-run` to preview. Exclude: `--exclude='*.tmp'`. Over SSH: `rsync -avz -e ssh ...`. Rsync is often faster than scp for large directory trees with small changes.

## Further Reading

- [rsync Documentation](undefined)