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>