anchor.diff:  %% of trace messages to be received, or a maximal frequency (`{Num, Millisecs}').
   %%
   %% Here are examples of things to trace:
  -%% 
  +%%
   %% <ul>
   %%  <li>All calls from the `queue' module, with 10 calls printed at most:
   %%      ``recon_trace:calls({queue, '_', '_'}, 10)''</li>
  
positive.code:             end;
          false ->
              exit(shell_funs_only)
      end. 
  
negative.code: %%%  |               -,        ,-               |
  %%%   '-,              '-,  ,-'              ,-'
  %%%      '-,_          _,-''-,_          _,-'
  %%%          '--------'        '--------'
  %%% '''
  %%%
  %%% If either the pid specification excludes a process or a trace pattern
  