Several special operators in PHP

// 错误屏蔽 ( @ )
$err2 = @(5 / 0);

//  执行（`.....`）
//  反引号可以把反引号之间的字符串当做shell命令执行，并返回输出结果
//  反引号运算符“`”的效果与函数 shell_exec() 相同
$listing = `ipconfig`;
echo  $listing;

//  类型 (instanceof)
//  测试一个变量是否为给定类的实例化的对象，或是一个接口的实现
class AA{}
$a = new AA;
if($a instanceof AA){
    echo '$a is Class "AA"';
}
if($a instanceof BB){
    echo '$a is Class "BB"';
}

The above has introduced several special operators in PHP, including related content. I hope it will be helpful to friends who are interested in PHP tutorials.