Ruby/File Directory/puts

module Enumerable
  def random_line
    selected = nil
    each_with_index { |line, lineno| selected = line if rand < 1.0/lineno }
    return selected.chomp if selected
  end
end
# Create a file with 1000 lines
open("random_line_test", "w") do |f|
  1000.times { |i| f.puts "Line #{i}" }
end
# Pick random lines from the file.
f = open("random_line_test")
f.random_line                                    # => "Line 520"
f.random_line                                    # => nil
f.rewind
f.random_line                                    # => "Line 727"

File.open("text.txt", "w") do |f|
  f.puts "This is a test"
end