RosettaCodeData/Task/File-size-distribution/J/file-size-distribution.j

    ((10x^~.),.#/.~) <.10 ^.1>. /:~;{:|:dirtree '~'
       1  2
      10  8
     100 37
    1000 49
   10000 20
  100000  9
 1000000  4
10000000  4