file_db.rb

class FileDb < Hash

  attr_accessor :path

  def initialize
    super
  end

  def self.open(path)
    f = self.new
    f.open(path)
    f
  end

  def open(path)
    @path = path
    if File.exist?(path)
      file = File.open(path, "r")
      self.parse(file.read)
    end
  ensure
    file.close if file
  end

  def parse(text)
    text.each_line do |line|
      line = line[0..-2] if line[-1] == "\n" # This seems to be necessary
      key_value = line.split("=")
      self[key_value[0]] = key_value[1]
    end
  end

  def save
    file_new = File.open(@path, "w+")
    self.each do |line_key, line_value|
      file_new.puts("#{line_key}=#{line_value}")
    end
    file_new.close
  end
end

file_db_test.rb

config = FileDb.open("config.dat")

config['apn']  = 'claro.com.br'
config['user'] = 'claro.com.br'
config['pass'] = 'claro.com.br'

config.save

puts config['apn']
puts config['user']
puts config['pass']

# reload/new
config = FileDb.open("config.dat")

puts config['apn']
puts config['user']
puts config['pass']

config['apn'] = 'tim.com.br'
config['user'] = 'tim.com.br'
config['pass'] = 'tim.com.br'

config.save

# reload/new
config = FileDb.open("config.dat")

puts config['apn']
puts config['user']
puts config['pass']

file_db_test_io.rb

while true
  odd = FileDb.new
  odd.open("odd")

  even = FileDb.open("even")

  odd_count = odd["count"] || 1
  even_count = even["count"] || 2

  IO.display(0, 0, "#{odd.path} #{odd_count}")
  IO.display(1, 0, "#{even.path} #{even_count}")

  odd["count"] = odd_count.to_i+2
  even["count"] = even_count.to_i+2

  odd.save
  even.save
  
  IO.read_key
end