show or set the system's host name
-I, --all-ip-addresses
       Display all network addresses of the host. This option enumerates all configured addresses on  all
       network  interfaces. The loopback interface and IPv6 link-local addresses are omitted. Contrary to
       option -i, this option does not depend on name resolution. Do not make any assumptions  about  the
       order of the output.
source manpages: ypdomainname