domainname(1) - man - phpMan

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  com‐
       plete  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  effec‐
       tive 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  geth‐‐
       ostname(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 ad‐
              dresses 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 re‐
              verse 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 ad‐
              dresses on all network interfaces. The loopback  interface  and  IPv6  link-local  ad‐
              dresses  are omitted. Contrary to option -i, this option does not depend on name reso‐
              lution. 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 AT et-inf.de>
       Bernd Eckenfels, <net-tools AT lina.de> (NIS and manpage).
       Michael Meskes, <meskes AT debian.org>



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