# File lib/main/daemon.rb, line 262
    def cmd_ping
      pid = Integer(IO.read(@pid_file)) rescue nil

      if pid
        signaled = false

        begin
          Process.kill('SIGALRM', pid)
          signaled = true
        rescue Object
          nil
        end

        if signaled
          STDOUT.puts(pid)
          exit
        end
      end
    end