Map ports to services (and back) for internet services. Using this CSV file
included in the distribution, creates and exports 4 hashes that map ports to
services and back, for UDP and TCP.
%TCPServices maps ports to TCP services
%TCPPorts maps service names to ports;
And idem with UDP instead of TCP.
say %TCPServices<80>; # should return www-http
say %UDPPorts<domain>; # should return 53
You can also use .keys to print the existing ports or services.