anchor.diff:  ;;;>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
   
   (define (usage script)
  -  (letn ((base-template "%s %-10s %s")
  -         (opt-template (append "\t -" base-template)))
  +  (letn ((base-template "%s %-20s\t%s")
  +         (short-opt-template (append "\t -" base-template))
  +         (long-opt-template (append "\t--" base-template))
  +         (cmd-template (append "\t  " base-template)))
       (println)
       (println version-string)
       (println)
  
positive.code:        (>= value 1)
         (<= value 100)))
  
  (define (set-level value)
    (! (format "xbacklight -set %s" value)))
  
  (define (display-bad-value level script)
    (print (format "\nERROR: the provided value '%s' is not valid " level))
  
negative.code: ;;;>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  
  (define (main script opts)
    (if (empty? opts)
      (get-brightness)
      (letn ((cmd-or-value (first opts))
             (int-level (integer cmd-or-value)))
        (cond
          ((= cmd-or-value "inc") (increment-brightness))
          ((= cmd-or-value "dec") (decrement-brightness))
          ((light-value? int-level) (set-level light-level))
          ('true (display-bad-value light-level script)))))
    (exit))
  
  ;;;>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  