#hostname -h

Usage: hostname [-v] [-b] {hostname|-F file}         set host name (from file)
       hostname [-v] [-d|-f|-s|-a|-i|-y|-A|-I]             display formatted name
       hostname [-v]                                 display host name
       {yp,nis,}domainname [-v] {nisdomain|-F file}  set NIS domain name (from file)
       {yp,nis,}domainname [-v]                      display NIS domain name
       dnsdomainname [-v]                            display dns domain name
       hostname -V|--version|-h|--help               print info and exit
Program name:
       {yp,nis,}domainname=hostname -y
       dnsdomainname=hostname -d
Program options:
    -s, --short            short host name
    -a, --alias            alias names
    -i, --ip-address       addresses for the host name
    -I, --all-ip-addresses all addresses for the host
    -f, --fqdn, --long     long host name (FQDN)
    -A, --all-fqdns        all long host names (FQDNs)
    -d, --domain           DNS domain name
    -y, --yp, --nis        NIS/YP domain name
    -b, --boot             set default hostname if none available
    -F, --file             read host name or NIS domain name from given file
Description:
   This command can get or set the host name or the NIS domain name. You can
   also get the DNS domain or the FQDN (fully qualified domain name).
   Unless you are using bind or NIS for host lookups you can change the
   FQDN (Fully Qualified Domain Name) and the DNS domain name (which is
   part of the FQDN) in the /etc/hosts file.