Provided by: hostname_3.12ubuntu1_i386 bug


       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


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

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

       dnsdomainname [-v]


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

       When called without any arguments, the  program  displays  the  current

       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).

       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/  (normally  by  reading  the contents of a file
       which contains the host name, e.g.  /etc/hostname).

       The FQDN (Fully Qualified Domain Name) of the system is the  name  that
       the resolver(3) returns for the host name, such as,
       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


       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

       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.


       -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 DNS 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, and
              avoid using this option; use hostname --all-fqdns instead.

       -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, --verbose
              Be verbose and tell what's going on.

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

       -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.


       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/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.


       Peter Tobias, <>
       Bernd Eckenfels, <> (NIS and manpage).
       Michael Meskes, <>