转自:http://www.xiuyuanjun.com/index.php/2021/10/17/linux-shell-%e4%b8%ad%e6%9f%a5%e7%9c%8b%e6%8c%87%e5%ae%9a%e7%9a%84%e7%ab%af%e5%8f%a3%e5%8f%b7%e5%8d%a0%e7%94%a8%e6%83%85%e5%86%b5/