gistfile1.rb

module Kernel
  alias :old_puts :puts
  def puts(val)
    old_puts val
    split = caller.first.split(':')
    yolo(split[0], split[1].to_i)
  end

  private
  def yolo(filename, line_number)
    f = File.new(filename, 'r+')
    f.each_with_index do |line, i|
      if i == line_number-1
        f.seek(-line.length, IO::SEEK_CUR)
        f.write(' ' * (line.length - 1))
        f.write("\n")
      end
    end
    f.close
  end
end


puts 'what'