$re = '/[^\w\d.\-]+/m';
$str = '����\\�p�a�t�r�i�c�k�-�t�e�s�t�-�f�i�l�e�.�t�x�t������x�SMB2';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php