Manual Hostname

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  gethost‐
      name(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 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 dns‐
      domainname 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 inter‐
             faces, and translates them to DNS domain names.  Addresses  that
             cannot be translated (i.e. because they do not have an appropri‐
             ate 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 enumer‐
             ates 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 reso‐
             lution.  Do not make any assumptions about the order of the out‐
             put.

      -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 success‐
             fully.

      -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)

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