php 用命令执行导出数据

被服务商迁移空间之后面板，ssh，数据库都无法进去，只有一个登陆ftp的账号信息，为了把站安全的迁移走或者备份，只能用php写个代码导出数据库
代码如下
[php]
<?php
$DbHost = ‘localhost’;
$DbUser = ‘root’;
$DbPwd = ‘root’;
$DbName = ‘webapi’;
echo ‘下载文件在当前路径下：’ . getcwd(); //获取当前文件路径
$fileName = ‘webapi_abckup_’ . date(‘YmdHis’, time()) . ‘.sql’;
$dumpFileName = getcwd() . "/{$fileName}";

/* header("Content-Disposition: attachment; filename=" . $fileName);
header("Content-type: application/octet-stream");
header("Pragma:no-cache");
header("Expires:0"); */

`mysqldump -h $DbHost -u$DbUser -p$DbPwd $DbName > $dumpFileName`;

?>
[/php]