DB<112> =du !!du
 
  DB<113> du /tmp
8	/tmp/pulse-lanx
4	/tmp/virtual-lanx.AqXwcf
...
  DB<114>  $DB::alias{du} 
 => "s\adu\a!!du\a"

##</code><code>##

!! cmd      Run cmd in a subprocess (reads from DB::IN, writes to DB::OUT)
        See 'O shellBang' too.