This is whois3, a very simple and generic whois client.

This client, unlike the "classic" whois client,
does not check for supported flags at the client side,
except for -h (whois host) and -p (whois port).

The syntax checks for flags are made at the server side.

The default host and port of whois3 is whois.ripe.net
at port 43 (or to be more exact, the tcp port specified
for whois in /etc/services).

Try whois3 help.