File::open("log.txt") do |f|
  current = ""
  count = 0
  f.each do |a|
    #抽出部は適宜変更
    target = /\[(.+)\]/.match(a)[1].split("/")[2][5, 2]
    if target != current
      count = 1
      current = target
      print "\n" + current + " : *"
    else
      print (count % 100 == 0) ? "*" : ""
      count = count + 1
    end
  end
end