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 gethostname(2) function.

       domainname   will   print   the  NIS  domainname  of  the  system.   domainname  uses  the
       gethostname(2)    function,    while    ypdomainname    and    nisdomainname    use    the
       yp_get_default_domain(3).

       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 sethostname(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  dnsdomainname  command
       (see THE FQDN below).

       The  host  name is usually set once at system startup in /etc/init.d/hostname.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 after 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 limitations so it should be avoided as well.

OPTIONS

       -a, --alias
              Display  the alias name of the host (if used). This option is deprecated and should
              not be used anymore.

       -A, --all-fqdns
              Displays all FQDNs of the machine. This option enumerates  all  configured  network
              addresses  on  all configured network interfaces, and translates them to DNS domain
              names. Addresses that cannot be translated  (i.e.  because  they  do  not  have  an
              appropriate  reverse  IP  entry)  are  skipped.  Note  that different addresses may
              resolve to the same name, therefore the output may contain  duplicate  entries.  Do
              not make any assumptions about the order of the output.

       -b, --boot
              Always  set  a hostname; this allows the file specified by -F to be non-existant or
              empty, in which case the default hostname localhost will be used  if  none  is  yet
              set.

       -d, --domain
              Display  the  name  of the DNS domain.  Don't use the command domainname to get the
              DNS domain name because it will show the NIS domain name and  not  the  DNS  domain
              name.  Use  dnsdomainname  instead. See the warnings in section THE FQDN above, and
              avoid using this option.

       -f, --fqdn, --long
              Display the FQDN (Fully Qualified Domain Name). A FQDN consists  of  a  short  host
              name and the DNS domain name. Unless you are using bind or NIS for host lookups you
              can change the FQDN and the DNS domain name (which is part  of  the  FQDN)  in  the
              /etc/hosts file. See the warnings in section THE FQDN above und use hostname --all-
              fqdns instead wherever possible.

       -F, --file filename
              Read the host name from the specified file. Comments (lines starting  with  a  `#')
              are ignored.

       -i, --ip-address
              Display  the network address(es) of the host name. Note that this works only if the
              host name can be resolved. Avoid using this option; use hostname --all-ip-addresses
              instead.

       -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.

       -s, --short
              Display the short host name. This is the host name cut at the first dot.

       -V, --version
              Print version information on standard output and exit successfully.

       -y, --yp, --nis
              Display the NIS domain name. If a parameter is given (or --file name  )  then  root
              can also set a new NIS domain.

       -h, --help
              Print a usage message and exit.

NOTES

       The  address  families  hostname  tries  when  looking  up  the  FQDN, aliases and network
       addresses of the host are determined by the configuration of your resolver.  For instance,
       on GNU Libc systems, the resolver can be instructed to try IPv6 lookups first by using the
       inet6 option in /etc/resolv.conf.

FILES

       /etc/hostname Historically this file was supposed to only contain the hostname and not the
       full  canonical  FQDN.  Nowadays most software is able to cope with a full FQDN here. This
       file is read at boot time by the system initialization scripts to set the hostname.

       /etc/hosts Usually, this is where one sets the domain name by aliasing the  host  name  to
       the FQDN.

AUTHORS

       Peter Tobias, <tobias@et-inf.fho-emden.de>
       Bernd Eckenfels, <net-tools@lina.inka.de> (NIS and manpage).
       Michael Meskes, <meskes@debian.org>