$re = '/[$](\{)?\w+(?(1)(?:[\/:].*})?)/m';
$str = '$TM_FILENAME
${TM_FILENAME/[\\.]/_/}
${1:OPT1|OPT2}';
preg_match_all($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