Ruby script ro rename all of a dir's files with random names

rename.rb

directory = 'directory/'
new_base_filename_length = 10

Dir.glob(directory + '*').sort.each do |old_filename|
  new_base_filename = ('a'..'z').to_a.shuffle[0, new_base_filename_length].join
  new_filename = directory + new_base_filename + File.extname(old_filename)
  File.rename(old_filename, new_filename)
end