Redirect non-www to www in .htaccess

Question

I have this in my .htaccess file:

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

but whenever I

Answer 1

RewriteCond %{HTTP_HOST} !^www\.domain\.com [NC]
RewriteRule (.*) http://www.domain.com/$1 [L,R=301]

This will redirect your domain which is not started with WWW It is not redirect your all sub domain.

It is useful.