What's this code line mean?

[camarosource]

if (preg_match ("/2\D\d\d\D[2-9|A]\w\d\d\d\d\d\d/", $vin))

I understand preg_match is used to match chars in the variable, in this case "$vin". But don't understand what exactly it's matching "/2\D\d\d\D[2-9|A]\w\d\d\d\d\d\d/"

Thanks

[goldbug]

Its attempting to match a $vin that begins with the number '2', followed by a non-digit character, then 2 digits, then a non-digit, then either the letter 'A' or a number between 2 and 9, then an alphanumeric, then 6 digits.

For example, it would match:

2A12B3C456789

an easier way to write it could be:

'/2\D\d{2}\D[2-9|a]\w\d{6}/i'

Check out:
http://www.php.net/manual/en/pcre.pattern.syntax.php