# File cli/ruby-debug/interface.rb, line 63
    def initialize()
      super
      @command_queue = []
      @restart_file = nil

      if @have_readline
        # take gdb's default
        @history_length = ENV['HISTSIZE'] ? ENV['HISTSIZE'].to_i : 256  
        @histfile = File.join(ENV['HOME']||ENV['HOMEPATH']||'.', 
                              FILE_HISTORY)
        open(@histfile, 'r') do |file|
          file.each do |line|
            line.chomp!
            Readline::HISTORY << line
          end
        end if File.exist?(@histfile)
      end
    end