domainname

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
       gethostname(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
       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-existent 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>



net-tools                         2009-09-16                       HOSTNAME(1)