The syntax of an ssh command line is
ssh [options] [user@]host [command]
where host, the name of the OpenSSH server (the remote system) you want to connect to, is the only required argument. The host can be a local system name, the FQDN (page 1069) of a system on the Internet, or an IP address.
With the command ssh host, you log in on the remote system host with the same username you are using on the local system. The remote system displays a shell prompt, and you can run commands on host. Enter the command exit to close the connection to host and return to the local system’s prompt. Include user@ when you want to log in with a username other than the one you are using on the local system. ...