merging files

file.rb

require 'pry-debugger'

output = File.new("output.txt", 'a')

nm1 = File.open("names.txt", 'r')
nm2 = File.open("names2.txt", "r")

#binding.pry
nm1.each_line do |n1|
  nm2.each_line do |n2|
    case n1 <=> n2
      when -1 then output.write n1; output.write n2
      when 0  then output.write n1
      when 1  then output.write n2; output.write n1
    end
    break
  end
end

output.close