Regular Expression and PHP

https://www.php.net/manual/en/function.preg-quote.php

The preg_quote($string) function is used in case the string you will use within a regular expression to match against a text may contain special characters that have a meaning in regular expression:

. \ + * ? [ ^ ] $ ( ) { } = ! < > | : - #

https://www.php.net/manual/en/function.preg-match-all

preg_match_all($pat,$string)