simple_port.ex

cmd = ~S"""
  ruby -e '
    STDOUT.sync = true
    context = binding

    while (cmd = gets) do
      eval(cmd, context)
    end
  '
"""

port = Port.open({:spawn, cmd}, [:binary])

Port.command(port, "a = 1\n")
Port.command(port, "a += 2\n")
Port.command(port, "puts a\n")

receive do
  {^port, {:data, result}} ->
    IO.puts("Elixir got: #{inspect result}")
end