$re = '/(?<=}{2}|^)(?!{{2}).*?(?={{2}|$)/s';
$str = '{{this should not be selected and the curly brackets too}} but this one { or } should be selected. So I want to exclude all text between an opening and closing curly brackets.
test{{this should not be selected and the curly brackets too}} but this one { or } should be selected. So I want to exclude all text between an opening and closing curly brackets.
{{this should not be selected and the curly brackets too}} but this one { or } should be selected. So I want to exclude all text between an opening and closing curly brackets.
test{{this should not be selected and the curly brackets too}} but this one { or } should be selected. So I want to exclude all text between an opening and closing curly brackets.';
preg_match_all($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