Section: Linux Programmer's Manual (1)Updated: 2009-09-16Local indexUp
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
is used to display the system's DNS name, and to display or set its hostname or
NIS domain name.
When called without any arguments, the program displays the current
will print the name of the system as returned by the
will print the NIS domainname of the system.
will print the domain part of the FQDN (Fully Qualified Domain Name). The
complete FQDN of the system is returned with
(but see the warnings in section
When called with one argument or with the
option, the commands set the host name or the NIS/YP domain name.
function, while all of the three
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
The host name is usually set once at system startup in
(normally by reading the contents of a file which contains
the host name, e.g.
You can't change the FQDN (as returned by
or the DNS domain name (as returned by
with this command. The FQDN of the system is the name that the
returns for the host name.
Technically: The FQDN is the name
returns for the host name returned by
The DNS domain name is the part after the first dot.
Therefore it depends on the configuration (usually in
how you can change it. Usually (if the hosts file is parsed before DNS or
NIS) you can change it in
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
is subject to the same limitations so it should be avoided as well.
Display the alias name of the host (if used). This option is deprecated
and should not be used anymore.
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.
Display the name of the DNS domain. Don't use the command
to get the DNS domain name because it will show the NIS domain name and
not the DNS domain name. Use
instead. Ssee the warnings in section
above, and avoid using this option.
-F, --file filename
Read the host name from the specified file. Comments (lines starting with
a `#') are ignored.
-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
above, and avoid using this option; use
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 DNS 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
Print a usage message and exit.
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
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.
Display the short host name. This is the host name cut at the first dot.
Print version information on standard output and exit successfully.
Be verbose and tell what's going on.
-y, --yp, --nis
Display the NIS domain name. If a parameter is given (or
) then root can also set a new NIS domain.
The address families
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
This file should only contain the hostname and not the full FQDN.