How to make an htaccess 301 redirect from a subdomain to a folder of the same name on the main domain?

Question

htaccess

There is a construction that redirects from a subdomain (city) in English ( https://city.site.ru/en/ ) to a folder of the same name on the main domain ( https://site.ru/en/city/ ):
RewriteCond %{HTTP_HOST} ^city\.site\.ru$ [NC]
RewriteRule ^en\/$ https://site.ru/en/city/ [R=301,L]
The goal is to make the rule common to all subdomains (cities ), like:
RewriteCond %{HTTP_HOST} ^( moscow|novosib|.... #etc. pieces 50# )\.site\.ru$ [NC]
#depending on which city the user chose
RewriteRule ^ en\/$ https://site.ru/en/ city / [R=301,L]
#and here I stalled, how to get the part about the city from %{HTTP_HOST} RewriteCond and insert instead of "city" into the RewriteRule?

Answer 1

RewriteEngine on

RewriteCond %{HTTP_HOST} ^(?>www\.|)(.+)\.site\.ru$ [NC]
RewriteRule ^en/$ https://site.ru/en/%1/ [R=301,L]