public function download() {
system('ssh root@**.**.**.** \n g7f8f9d90s0s8');
system("cd /data/logs/{$_POST['server']}");
system("tar -zcvf /var/ftp/{$_POST['server']}_{$_POST['date']}.tar.gz ./*{$_POST['date']}*.log", $out);
if ($out != false) {
system("touch 已打包完成.txt");
}
system("exit");
}