<?php

$counterFile = "count.txt";

function displayCounter($counterFile) {
$fp = fopen($counterFile,"rw");
$num = fgets($fp,5);
$num += 1;
print "计数器"."$num"."";
exec( "rm -rf $counterFile");
exec( "echo $num > $counterFile");
}

if (!file_exists($counterFile)) {
exec( "echo 0 > $counterFile");
}

displayCounter($counterFile);

?>

count.txt 已设为777
在windows服务器上一切正常
在linux服务器上能正确显示初始数加1,但累计数写不进txt中.好象exec的语句都被禁止了,有什么解决方法?