gistfile1.rb

 def format_number!
    if self.instance_of? Cpf
      @numero =~ /(\d{3})\.?(\d{3})\.?(\d{3})-?(\d{2})/
      @numero = "#{$1}.#{$2}.#{$3}-#{$4}"
    else
      @numero =~ /(\d{2})\.?(\d{3})\.?(\d{3})\/?(\d{4})-?(\d{2})/
      @numero = "#{$1}.#{$2}.#{$3}/#{$4}-#{$5}"
    end
  end