Simple portscanner in Erlang

%%
%% simple portscanner written in simple erlang :)
%%
-module(portscanner).
-export([start/0]).
-author({"Christopher Bertels", "bakkdoor@flasht.de"}).
 
 
%% start portscanner process.
start() ->
    Host = io:get_line("host?\n") -- "\n",
    Start = list_to_integer(io:get_line("start port?\n") -- "\n"),
    End = list_to_integer(io:get_line("end port?\n") -- "\n"),
    io:format("host: ~s, start: ~p, end: ~p~n~n", [Host, Start, End]),
 
    start_threads(Host, Start, End).
 
 
%% start End - Start threads, each connecting to each port in that range.
start_threads(Host, Start, End) when Start > End ->
    io:format("started all scanning processes on ~p~n", [Host]);
 
start_threads(Host, Start, End) when Start =< End ->
    spawn(fun() ->
		  connect(Host, Start)
	  end),
    start_threads(Host, Start + 1, End).
 
 
%% connects to Host on Port and prints a message, if connetion works.
connect(Host, Port) ->
    Connection = gen_tcp:connect(Host, Port, [binary, {packet, 0}]),
    case Connection of
	{ok, S} ->
	    io:format(">> Port open ~s:~p~n", [Host, Port]),
	    gen_tcp:close(S);
	_ ->
	    none
    end.