Elixir to C# port example, based on http://stackoverflow.com/a/25342599

portexample.ex

defmodule PortExample do
    def start_exe(exe_name, arguments) do
        # start the executable process for what settings mean see http://erlang.org/doc/man/erlang.html#open_port-2
        port = Port.open({:spawn_executable, exe_name}, [{:args, arguments}, :stream, :binary, :exit_status, :hide, :use_stdio, :stderr_to_stdout])                
        # spawn a listening process
        handle_output(port)   
        # return the port
        port                       
    end
        
    def handle_output(port) do
        spawn(__MODULE__, :listen, [port])
    end
    
    def listen(port) do
        receive do
            {^port, {:data, data}} ->
                IO.puts(data)
                listen(port)
            {^port, {:exit_status, status}} ->
                status
        end        
    end
    
end

# // date.exe console app that echos message along with date
#
# class Program
# {
#    static void Main(string[] args)
#    {
#        string input = "";
#        while (true)
#        {
#            input = Console.ReadLine();
#            if (input == "exit") break;
#            Console.Out.WriteLine($"{ DateTime.UtcNow} - {input}");
#        }
#        Console.WriteLine("exiting ...");
#      }
# }

# *** on the iex command line ***
#
# c("portexample.ex")
# port = PortExample.start_exe("date", [])
# Port.command(port, "message from elixir\n")
# 
# flush to see message