htaccess redirect subdomain to folder and non-www to www

Question

sub.domain.com redirect to www.domain.com/sub redirects using:

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

domain.com/sub to www.domain.com/sub is where I'm stuck.The solutions I've found always drop the /sub/ folder when rewriting the www.

Answer 1

This works:

RewriteEngine on
RewriteBase /

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

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