progress_stdout.rb

class MyClass

  def self.my_method
    100.times do |index|
      yield 100, index + 1 if block_given?
    end
  end

end


MyClass.my_method do |total, index|
  $stdout.print "\r"
  $stdout.print index
  $stdout.print "%"
  $stdout.flush
  sleep 0.03
end

puts