Htaccess to force use WWW for mutlidomain

I found this code to force using www.

RewriteEngine On
RewriteCond %{HTTP_HOST} !^www.example.com$
RewriteRule ^(.*)$ http://www.example.com/$1 [R=301]

But i have many domain that po开发者_高级运维inted to same directory. So i need a version of this code for multiple domains. It must run on any domain, is it possible ?

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This should work:

RewriteCond %{HTTP_HOST} ^[^.]+\.[^.]+$
RewriteRule ^(.*) http://www.%{HTTP_HOST}/$1 [R=301]

It will redirect all request without a subdomain to www.domainame.tld.