Apache: Permanent Redirect to HTTPS with Wildcard
As RedirectMatch Directive of Apache 2.4 httpd says:
Syntax: RedirectMatch [status] regex URL
This directive is equivalent to Redirect, but makes use of regular expressions, instead of simple prefix matching.
Example:
RedirectMatch "(.*)\.gif$" "http://other.example.com$1.jpg"
Apache uses PCRE compatible regexp's.
But normally it should be enought to use:
Redirect permanent / https://www.example.com/Last but not least the important part: Redirect only matches URL-path and not the complete URL!
So you better add a VirtualHost configuration for every subdomain you are using.