HOSTNAME(1)                Linux Programmer’s Manual                HOSTNAME(1)

NAME
       hostname - show or set the system’s host name
       domainname - show or set the system’s NIS/YP domain name
       ypdomainname - show or set the system’s NIS/YP domain name
       nisdomainname - show or set the system’s NIS/YP domain name
       dnsdomainname - show the system’s DNS domain name

SYNOPSIS
       hostname  [-a|--alias] [-d|--domain] [-f|--fqdn|--long] [-A|--all‐fqdns]
       [-i|--ip‐address] [-I|--all‐ip‐addresses] [-s|--short] [-y|--yp|--nis]
       hostname [-b|--boot] [-F|--file filename] [hostname]
       hostname [-h|--help] [-V|--version]

       domainname [nisdomain] [-F file]
       ypdomainname [nisdomain] [-F file]
       nisdomainname [nisdomain] [-F file]

       dnsdomainname

DESCRIPTION
       Hostname is used to display the system’s DNS name, and to display or set
       its hostname or NIS domain name.

   GET NAME
       When called without any arguments,  the  program  displays  the  current
       names:

       hostname  will  print the name of the system as returned by the gethost‐
       name(2) function.

       domainname will print the NIS domainname of the system.  domainname uses
       the gethostname(2) function, while ypdomainname  and  nisdomainname  use
       the getdomainname(2).

       dnsdomainname  will  print  the domain part of the FQDN (Fully Qualified
       Domain Name). The complete FQDN of the system is returned with  hostname
       --fqdn (but see the warnings in section THE FQDN below).

   SET NAME
       When  called  with  one argument or with the --file option, the commands
       set the host name or the NIS/YP domain name.  hostname uses the sethost‐
       name(2) function, while all of the three  domainname,  ypdomainname  and
       nisdomainname  use  setdomainname(2).  Note, that this is effective only
       until the next reboot.  Edit /etc/hostname for permanent change.

       Note, that only the super‐user can change the names.

       It is not possible to set the FQDN or the DNS domain name with the  dns‐
       domainname command (see THE FQDN below).

       The host name is usually set once at system startup in /etc/init.d/host‐
       name.sh  (normally  by reading the contents of a file which contains the
       host name, e.g.  /etc/hostname).

   THE FQDN
       The FQDN (Fully Qualified Domain Name) of the system is  the  name  that
       the  resolver(3) returns for the host name, such as, ursula.example.com.
       It is usually the hostname followed by the DNS domain name (the part af‐
       ter the first dot).  You can check the FQDN using hostname --fqdn or the
       domain name using dnsdomainname.

       You cannot change the FQDN with hostname or dnsdomainname.

       The recommended method of setting the FQDN is to make the hostname be an
       alias for the fully qualified name using /etc/hosts, DNS,  or  NIS.  For
       example,  if  the  hostname  was  "ursula",  one  might  have  a line in
       /etc/hosts which reads

              127.0.1.1    ursula.example.com ursula

       Technically: The FQDN is the name getaddrinfo(3) returns  for  the  host
       name  returned by gethostname(2).  The DNS domain name is the part after
       the first dot.

       Therefore it depends on the configuration of the  resolver  (usually  in
       /etc/host.conf)  how you can change it. Usually the hosts file is parsed
       before DNS or  NIS,  so  it  is  most  common  to  change  the  FQDN  in
       /etc/hosts.

       If  a  machine has multiple network interfaces/addresses or is used in a
       mobile environment, then it may either have multiple FQDNs/domain  names
       or none at all. Therefore avoid using hostname --fqdn, hostname --domain
       and dnsdomainname.  hostname --ip‐address is subject to the same limita‐
       tions so it should be avoided as well.

OPTIONS
       -a, --alias
              Display the alias