I’ve talked before about setting the permalink options, but recently I’ve had reason to re-visit those settings on some sites. At the time I installed WordPress on those sites, I was using a webhoster that did not allow me to set the necessary options in the .htaccess file because the so-called “mod_rewrite” option was not available.
After moving those blogs onto my own server, I kept the structure in place. That meant URLs containing “index.php” in them, to trick WordPress into using meaningful permalinks.
Obviously, I didn’t want the old permalinks to become invalid, or for Google to think it was duplicate content.
Here’s how I solved the problem, and how you too can change your permalink structure at a later date:
1. Log into WordPress as an administrator.
2. Click on “add new” in the plug-ins section of the sidebar, and search for “Dean’s Permalinks Migration”
3. Install and activate the plug-in, and then click on “PermalinksMigration” in the “Settings” part of the sidebar
4. Your current permalink settings should already be entered, so if everything is correct you only need to click on “Update options”.
5. Now click on “Permalinks” in the “Settings” part of the sidebar, enter or select your new settings, and click on “Save Changes”
Now any links to the old URL will be re-directed to the new one using the so-called “301 redirect” method, meaning that search engines will realise that the page has effectively “moved” and not consider it to be duplicate content.