#!/usr/bin/env ruby

files = []
(0..1).each { |i| files << File.new(ARGV[i], 'r') }
(2..3).each { |i| files << File.new(ARGV[i], 'w') }
files.each { |f| f.set_encoding('utf-8') }

while line_f = files[0].gets
  line_e = files[1].gets 
  line_f.strip!; line_e.strip!
  next if line_f=='' || line_e==''
  files[2].write line_f+"\n"
  files[3].write line_e+"\n"
end

files.each { |f| f.close }