anchor.diff:              % this ensure the real os process is killed when this process dies.
               erlang:monitor(process, Pid),
               receive _ -> ok end,
  -            os:cmd(?b2l(iolist_to_binary(KillCmd)))
  +            killer(?b2l(KillCmd))
           end),
       OsProc =
       lists:foldl(fun(Opt, Proc) ->
  
positive.code: code_change(_OldVsn, State, _Extra) ->
      {ok, State}.
  
  
negative.code: -behaviour(gen_server).
  
  -export([start_link/1, start_link/2, start_link/3, stop/1]).
  -export([set_timeout/2, prompt/2, prompt_many/2, killer/1]).
  -export([send/2, writeline/2, readline/1, writejson/2, readjson/1]).
  -export([init/1, terminate/2, handle_call/3, handle_cast/2, handle_info/2, code_change/3]).
  
  