dp.rb

#!/usr/bi/env ruby

input_file = ARGV[0]
output_file = ARGV[1]

strings = []

File.readlines(input_file).each do |line|
  strings << [line.length, line]
end

strings.sort_by! { |array| array[0] }

strings.each do |s|
  open(output_file, 'a') { |f|
    f.puts s[1]
  }
end