anchor.diff:  
   -behavior(gen_server).
   -behavior(ns_log_categorizing).
  +
  +-include("ns_common.hrl").
   
   %% API
   -export([start_link/4]).
  
positive.code:     end.
  
  handle_info({_Port, {data, Msg}}, State) ->
      error_logger:info_msg("Message from ~p: ~s~n", [State#state.name, Msg]),
      {noreply, State};
  handle_info({_Port, {exit_status, Status}}, State) ->
      error_logger:info_msg("~p exited with status ~p~n",
  
negative.code:                           [Cmd, Pwd, Args, Opts]),
      open_port({spawn_executable, Cmd}, Opts).
  
  log_messages(Name, L) ->
      receive
          {_Port, {data, Msg}} ->
              log_messages(Name, [Msg|L])
      after 0 ->
              ?log_info("Message from ~p:~n~s",
                        [Name, lists:append(lists:reverse(L))])
      end.
  
  
  %% ns_log stuff
  
  