ryanshoover

Changing your link structure in WordPress can lead to all of your old links breaking and returning a “404”. But no more! If someone goes to an old link for your site, I’ll find the new link and redirect them there automatically.
No configuration. No one-by-one setting of the new link structures. No wrestling with complicated regex patterns. Just install me and relax.
Redirect 404s works with posts, pages, and custom post types (like ecommerce products).
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<li>Note – the plugin only works for permalink structures where the last “chunk” of the URL is the post name (also called the slug).</li>
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Redirect Old Links

Did you change your permalink structure and now have old links "404ing"? I'll redirect those old links to their new one for you.

keith graham

The Link Fixer Plugin (note the name change from Permalink Finder) detects when WordPress cannot find a permalink. Before it generates the 404 error the plugin tries to locate any posts with similar words. It does this by searching through the database trying to find any of the word values from the bad link. It takes the best match and then, rather than issuing a 404 error, it sends back a redirect to the correct page. 
Users will see the page that they are looking for, and search engine spiders will see the 301 redirect and update their databases so that the page appears correctly in searches.
The configuration panel allows a user to select how the plugin finds a missing page. The plugin counts the number of words that match to a post. By default, a two word match is sufficient to cause a redirect to the found page. False positives are possible, especially if the user selects a one word match. Increasing the number of words, however makes it unlikely that the plugin will ever find a match. You may eliminate numbers from the search. You may specify that a list of common English words like “the”, “and”, “who”, “you”, etc., not be considered in finding the correct permalink.
Optionally, the plugin will redirect hits on index.html, index.htm, and index.shtml to the blog home page. This is useful when a website previously used a non-php home page.
If WordPress detects a 404 error on robots.txt, sitemap.xml, crossdomain.xml, favicon.ico, or apple-touch-icon.png it will provide a default version.
The plugin will also optionally keep track of the last few 404’s or redirects. This is useful to find out what pages are missing or named badly that keep causing 404 errors or forcing redirects.
<h3>Support</h3>
This plugin is free and I expect nothing in return. Please rate the plugin at: https://wordpress.org/extend/plugins/permalink-finder/ 
If you wish to support my programming, You can donate or buy my book: 
https://linktr.ee/keithpgraham

Link Fixer

Never get a 404 page not found again. If you have restructured or moved your blog, this plugin will find the right post or page every time.

Redirect Old Links vs Link Fixer