$re = '/^(?:
(?P<entity>[^:]+)
(?::(?P<mode>[^:]+))?
(?P<paths>
(:(?P<path>[^:]+))+
)?
)
$/mx';
$str = 'teams
teams:read
teams:read:abc123
teams:read:abc123:def234';
preg_match_all($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