Matching UTF Characters with preg_match in PHP: (*UTF8) Works on Windows but not Linux

Question

I have a simple regular expression to check a username:

preg_match(\'/(*UTF8)^[[:alnum:]]([[:alnum:]]|[ _.-])+$/i\', $username);

In local t

Answer 1

Try it by describing the characters by its Unicode character properties:

preg_match('/^\p{L}[\p{L} _.-]+$/u', $username)