anchor.diff:      {Opts, _} = rebar_state:command_parsed_args(State),
       case debug_get_value(apps, Opts, no_value,
                            "Found shell apps from command line option.") of
  -        no_value -> no_value;
  +        no_value ->
  +            case debug_get_value(start_clean, Opts, false,
  +                                "Found start-clean argument to disable apps") of
  +                false -> no_value;
  +                true -> []
  +            end;
           AppsStr ->
               [ list_to_atom(AppStr)
                 || AppStr <- rebar_string:lexemes(AppsStr, " ,:") ]
  
positive.code:                          "shell. (E.g. --apps app1,app2,app3) Defaults "
                           "to rebar.config {shell, [{apps, Apps}]} or "
                           "relx apps if not specified."},
                          {user_drv_args, undefined, "user_drv_args", string,
                           "Arguments passed to user_drv start function for "
                           "creating custom shells."}]}
  
negative.code:             ?DEBUG("No script_file specified.", []),
              ok;
          "none" ->
              ?DEBUG("Shell script execution skipped (--script none).", []),
              ok;
          RelFile ->
              File = filename:absname(RelFile),
  