If you don't want to install, or maintain, s5cmd yourself:

  ssh user@rsync.net s5cmd
  
  Password:
  NAME:
  s5cmd - Blazing fast S3 and local filesystem execution tool
  
  USAGE:
  s5cmd [global options] command [command options] [arguments...]

If you move data between clouds, you don't need to use any of your own bandwidth ...