How can I use a regular expression to validate month input?

Question

I am setting up this example Perl snippet to validate for months in a date:

Some scenarios I want to accept are:

MM M

#!/usr/bin/perl
use str         


        

Answer 1

If you really like to use regex, you need to put ^ and $, like

"^(0?[1-9]|1[012])$"

it will not match 13, 14 ....