Are the words contained in the regular expression?

Question

Regular Expressions

Good afternoon,
I'm trying to make a check for the url, whether the word exists in it or not.
http://site.ru/{msk|spb|region}/page
That is, the url should be site.ru, and between the curly braces something can be, but something is not.
It turns out such a url site.ru/page
And such site.ru/msk/page
Must be valid
I try like this:
/site.ru\/(?:^(?!msk|spb\/).*$)page/i
What - something nifiga, already tortured ...

Answer 1

regular season
it is not entirely clear what you are doing. if you just check the line or make htaccess

RewriteCond %{REQUEST_URI}  ^(\/)*(msk|spb|region)*\/page
RewriteRule ^(.*)$ /go to? [R=301,L]