elixir_tail.exs

defmodule ElixirTail do
  def tail path do
    Stream.resource(fn -> File.open!(path) end,
    fn file ->
      case IO.read(file, :line) do
        :eof ->
          :timer.sleep 10
          {[], file}
        data ->
          IO.write data
          {[data], file}
      end
    end,
    fn file -> File.close(file) end)
    |> Stream.run
  end
end

A rust version