hostid—Set or print system’s host ID.
hostid [–v] [ decimal-id ]
The hostid command prints the current host ID number in hexadecimal and both decimal and hexadecimal in parenthesis if the –v option is given. This numeric value is expected to be unique across all hosts and is normally set to resemble the host’s Internet address.
Only the superuser can set the hostid by giving an argument. This value is stored in the file /etc/hostid and need only be performed once.