rsync -v -e "ssh -p 5757" firstname.lastname@example.org:/opt/test.txt
-v - verbose
-e - to secify any remote shell you like
--dry-run - will list files that will get copied without actually being copy. This can be used if you’re not yet ready to copy any files or want to verify what all data will get copied using the command.
Once you verified the data, you can actually copy the data by removing --dry-run option from above command.