sftp -V (return code: 255)
ssh: Could not resolve hostname version: Name or service not known
Couldn't read packet: Connection reset by peer
sftp -h (return code: 1)
usage: sftp [-1246aCfpqrv] [-B buffer_size] [-b batchfile] [-c cipher]
[-D sftp_server_path] [-F ssh_config] [-i identity_file] [-l limit]
[-o ssh_option] [-P port] [-R num_requests] [-S program]
[-s subsystem | sftp_server] host
sftp [user@]host[:file ...]
sftp [user@]host[:dir[/]]
sftp -b batchfile [user@]host