$re = '/^( *urls *= *\[)(("(?!tac-temp10)([a-zA-Z0-9_-]*)",? *)*)(\] #tac)$/m';
$str = '[[inputs.ping]]
urls = ["tac-temp1","tac-temp2","tac-temp3","tac-temp4"] #tac
count = 30
timeout = 15.0
[inputs.ping.tags]
name = "tac"
[[inputs.ping]]
urls = ["prod-temp1","prod-temp2", "prod-temp3","prod-temp4"] #prod
count = 30
timeout = 15.0
[inputs.ping.tags]
name = "prod"
[[inputs.ping]]
urls = ["test-temp1","test-temp2", "test-temp3","test-temp4"] #test
count = 30
timeout = 15.0
[inputs.ping.tags]
name = "test"';
preg_match_all($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