$re = '/ghf(?:0[1-9]|[1-4][0-9]|5[012])[0-9]{3}[a-zA-Z]{2}_v[0-9]{2}\.pdf/m';
$str = 'ghf50001BE_v02.pdf
ghf53001BE_v02.pdf
ghf01001BE_v02.pdf
ghf52001BE_v02.pdf
ghf13001BE_v02.pdf';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($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