Create a subdomain for an addon domain

I have my hosting for site.com (public_html).
On my hosting I have also site2.com which is in public_html/site2.

I want to create subdomain.site2.com that has the content of public_html/site2/subdomain.

How can I do this? When someone visit site2.com/subdomain he should be redirected (301) to subdomain.site2.com.

Some help?
Thank you in advance for any reply!

 

Create a subdomain site.site.com and create a redirect via .htaccess.

 

And what should I insert into my .htaccess?

 

Try this one.

RewriteEngine On
Options +FollowSymLinks
RewriteBase /

RewriteCond %{http_host} ^site.com [nc]
RewriteRule ^(.*)$ http://www.site.com/$1 [L,R=301]

RedirectMatch 301 ^/subfolder/(.*)$ http://subdomain.site.com/$1

Code (markup):

 

Ok, I added this line:

RedirectMatch 301 ^/subfolder/(.*)$ http://subdomain.site.com/$1

Code (markup):

​

... to public_html/site2.

and now it works. When I go to site2.com/subdomain/ I get redirected to subdomain.site2.com. Great!

The problem now is that it doesn't load anything! I have a software that should start the install process when I visit the page, but nothing. Error loading the page. Maybe I should see if something is wrong in cPanel?

 

Then point the subdomin to a subfolder where the script is installed.