What is Hostname?
The Hostname command is used to show or set the system’s host name under Linux operation system.
DESCRIPTION
Hostname 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 Hostname command will display the current names of system.
When the hostname called with one argument or with the –file option, it will set the system’s host name based on the name string that you specified.
Hostname Syntax
The below is the Syntax of Hostname command:
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]
Hostname Options
Let’s see the each opations of hostname command:
-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 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 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, and avoid using this option; use hostname –all-fqdns instead.
-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. Contrary to option -i, this option does not depend on name resolution. 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.
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.