# zsync > Partial/differential file downloader. > HTTPS is not supported - use HTTP URLs only. > See also: `rsync`. > More information: . - Download a file using a `.zsync` control file: `zsync {{path/to/url.zsync}}` - Use a local file as a seed to avoid re-downloading unchanged parts: `zsync -i {{path/to/existing_file}} {{path/to/url.zsync}}` - Save the updated file under a specific name: `zsync -i {{path/to/existing_file}} -o {{path/to/new_file}} {{path/to/url.zsync}}` - Resume a partial download and keep the temporary file: `zsync -k {{path/to/url.zsync}}` - Run in quiet mode with minimal output (no progress bar, download rate, or ETA display): `zsync -q {{path/to/url.zsync}}`