使用蜂鳴器通知某指令完成

1.先寫一隻能夠使蜂鳴器發出聲音的程式

  //b2.c
  #include   
  #include   

  void   play(unsigned   int*   freq,   unsigned   int*   delay);

  int main(int argc, char* argv[])
  {
        speaker(330, 5);
        speaker(  0, 5);
        speaker(330, 5);

        return 0;
  }
  
  int   speaker(unsigned   int   freq,unsigned   int   delay)
  {   static   int   flag=0,bit;
          if(flag==0)
          {
                  flag=1;
                  iopl(3);
          }
          outb(0xb6,0x43);
          outb((freq   &   0xff),0x42);
          outb((freq   >>   8),0x42);
          bit=inb(0x61);
          outb(3   |   bit,0x61);
          usleep(10000*delay);
          outb(0xfc   |   bit,0x61);
        return;
  }

2.beep：一個shell script使b2在指令完成時執行

$*
sudo ./b2

3.把b2 and beep放至/bin

4.由於b2發出聲音要有root的權限，所以b2擁有者要設為root，然後對beep作setuid
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