Communicate with another
host using the TELNET protocol.
host may be either a name or an Internet address (dot format).
telnet has a command mode (indicated by the telnet> prompt)
and an input mode (usually a login session on the
host is given, telnet defaults to command mode.
You can also enter command mode from input mode by
typing the escape character CTRL-]. In command mode, type ? or
help to list the available commands.