ruby - How do I know what ports are on my Macbook? -

ruby - How do I know what ports are on my Macbook? -

i'm trying go through particular code illustration "the grounded rubyist" regarding tcpserver , threads. code below:

require 'socket' server = tcpserver.new(3939) connect = server.accept connect.puts "hi. here's date." connect.puts 'date' connect.close server.close

how know port on macbook? docs has 2000 in example. however, when seek both of these numbers code doesn't execute, continues hang indefinitely.

how can check if these numbers verified ports? tried telnetting port number , connection refused everytime.

server.accepts waits client connect server. if not happen, keeps waiting. run code, open terminal , type:

require 'socket' s = tcpsocket.new 'localhost', 3939

at point create tcpsocket, connect server. cause rest of code execute. can check socket:

while line = s.gets # read lines socket puts line # , print them end

ruby