Ssh (Secure Shell) a program for logging into a remote
machine and for executing commands in a remote machine.
X11 connections and arbitrary TCP/IP
ports can also be forwarded over the secure channel. If the username in
the host machine and the remote machine is same, you can just type the
machine name or else you have to supply the username with option
-l. For example you are in the local machinelightning and you want
to login to stat.washington.edu with the same username you can
type
lightning:~ > ssh stat.washington.edu
If you have username name_one in lightning and name_two in
stat.washington.edu you should type
lightning:~ > ssh -l name_two stat.washington.edu
For machines in the local server you may not type the whole name e.g if you
want to ssh from lightning to deming you type
lightning:~ > ssh deming