You can resume a partially downloaded file using rsync by using the --partial and --continue options. The --partial option allows rsync to keep partially transferred files, and the --continue option tells rsync to resume a transfer that was previously interrupted.
For example, to resume a file transfer using rsync, you can run the following command:
rsync --partial --progress --rsh=ssh user@remote:/path/to/file /local/destination/folder/
If the file transfer was previously interrupted, rsync will continue from where it left off and complete the transfer.