How to make such a redirect?

Question

htaccess

There are four domains: site.ru, www.site.ru and site.su, www.site.su.
How to make a redirect from ru domain to su, taking into account www as well?
The option for the htaccess file is suitable. Thanks in advance.

Answer 1

On site.ru you redirect to site.su
On www.site.ru you redirect to www.site.su
.htaccess:

<IfModule mod_rewrite.c>
  RewriteEngine On
        RewriteCond %{HTTP_HOST} ^site.ru$ [NC]
  RewriteRule ^(.*)$ https://site.su/$1 [R=301,L]
</IfModule>

<IfModule mod_rewrite.c>
  RewriteEngine On
        RewriteCond %{HTTP_HOST} ^www.site.ru$ [NC]
  RewriteRule ^(.*)$ https://www.site.su/$1 [R=301,L]
</IfModule>

Answer 2

RewriteEngine On
RewriteCond %{HTTP_HOST} ^(.+\).ru$ [NC]
RewriteRule ^(.*)$ https ://%1.su/$1 [R=301,L]
ps
no state