Nginx 遇到502 Bad Gateway 自动重启的脚本代码

#!/usr/bin/php
<!--$url = 'http://www.jb51.net';
$cmd = '/usr/local/php/sbin/php-fpm restart';

for($i = 0; $i < 5; $i ++){ $exec = "curl connect-timeout 3 -I $url 2>/dev/null";
$res = shell_exec($exec);

if(stripos($res, '502 Bad Gateway') !== false){
shell_exec($cmd);
exit();
}
}
-->