# File lib/simp/cli/config/logging.rb, line 36
    def open_logfile(file)
      @file.close if @file
      @file = File.new(file, 'w')  # overwrite existing file
      @file.sync = true            # flush after every write
      @file_logger = ::Logger.new(@file)
      @file_logger.formatter = proc do |severity, datetime, progname, msg |
        timestamp = datetime.strftime('%Y-%m-%d %H:%M:%S')
        "#{timestamp}: #{msg}\n"
      end
      @file_logger.level = @file_level
    end