<?^open Unix open Printf
    let st = stat "robots.txt" 
    let sz = float_of_int st.st_size 
    let fmt d u = lift(sprintf "%.1f%s" (sz/.d) u) ?>
<?match arg "unit" with
      | Some "M" -> puts .~(fmt 1048576. "M")
      | Some "k" -> puts .~(fmt 1024. "k")
      | _          -> puts .~(fmt 1. "") ?>