$re = '/({word1\/)([\w-]+)\/(\w+)/';
$str = '{word1/G_KP8zXsDp8/word2}
{word1/GKP8zXsDp8/word2}
{word1/G-KP8zXsDp8/word2}';
preg_match_all($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