hostid prints the numeric identifier of the current host in hexadecimal. This command accepts no arguments. The only options are --help and --version. See Common options.
For example, here's what it prints on one system I use:
$ hostid
1bac013d
On that system, the 32-bit quantity happens to be closely related to the system's Internet address, but that isn't always the case.
An exit status of zero indicates success, and a nonzero value indicates failure.