Ann Smarty provides insight into preventing duplicate content with .htaccess files on Linux servers with the Apache Mod-Rewrite module enabled. .
One of the four examples includes
changing domain names. "When you need to change your domain name you should use 301 redirect to preserve your PageRank (and rankings)," she writes. "You can do it by using this code in your .htaccess
file: Options +FollowSymlinks. RewriteEngine on rewriterule(.*) http://www.newdomain.com/$1 [r=301,nc]."
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