php定时执行脚本

ignore_user_abort(); // run script. in background
set_time_limit(0); // run script. forever
$interval=30; // do every 0.5 minutes...
do{
    $fp = fopen(‘interval.txt‘,‘a‘);
    fwrite($fp,‘1‘);
    fclose($fp);
    sleep($interval); // wait 0.5 minutes
}while(true);