On Unix-like operating systems, the hostname command shows or sets the system hostname.

This page covers the GNU/Linux version of hostname.

Description

hostname is used to display the system’s DNS name, and to display or set its hostname or NIS (Network Information Services) domain name.

  • Description
  • Syntax
  • The FQDN
  • Files
  • Examples
  • Related commands
  • Linux commands help

When called without any arguments, hostname displays the name of the system as returned by the gethostname function.

When called with one argument or with the –file option, hostname sets the system’s hostname using the sethostname function. Only the superuser can set the hostname.

The hostname is usually set once at system startup in the script /etc/init.d/hostname.sh normally by reading the contents of a file which contains the hostname, e.g., /etc/hostname.

Syntax

hostname [-v] [-a|–alias] [-d|–domain] [-f|–fqdn|–long] [-A|–all-fqdns] [-i|–ip-address] [-I|–all-ip-addresses] [-s|–short] [-y|–yp|–nis]

hostname [-v] [-b|–boot] [-F|–file file name] [hostname]

hostname [-v] [-h|–help] [-V|–version]

Options

The FQDN

The FQDN (fully qualified domain name) of the system is the name that the resolver returns for the hostname, such as mysubdomain.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 “mysubdomain”, 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 returns for the hostname returned by gethostname. 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.

Files

Examples

hostname

Displays the system hostname.

hostid — Print the numeric identifier for the current host.uname — Print information about the current system.