$re = '/data-reveal="(.+)/';
$str = '<a class="button block left icon-phone" data-reveal="\\u06f0\\u06f9\\u06f3\\u06f6\\u06f5\\u06f6\\u06f8\\u06f1\\u06f6\\u06f2\\u06f1" href="#">';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
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