Manual: ypdomainname

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, ypdomain‐
       name  and  nisdomainname	 use setdomainname(2).	Note, that this is effective only until the next re‐
       boot.  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 us‐
       ing 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  quali‐
       fied  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  gethost‐
       name(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 and 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. Con‐
	      trary  to	 option	 -i, this option does not depend on name resolution. Do not make any assump‐
	      tions 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, 
       Bernd Eckenfels,  (NIS and manpage).
       Michael Meskes, 

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