craigsimps

This is a super-simple plugin which will turn WordPress’ default <code>/?s=query%20terms</code> into <code>/search/query+terms/</code> if you have pretty permalinks enabled.
This is something which I have been placing into a theme include or in a core functionality plugin until recently, but it makes sense to separate this functionality out into an individual plugin so it can be switched on and off independently.
The plugin has no administrative interface or control panel. Activation turns it on, deactivation turns it off. Once activated, performing a search using the standard WP search widget should give you a much nicer search URL.

Simple Search Rewrite

Redirects search results from /?s=query to /search/query/, and converts %20 to +.

Kailey (trepmal)

Shaun Scovil

It was brought to my attention shortly after releasing this plugin that WordPress automatically flushes 
rewrite rules when you visit WP-Admin > Settings > Permalinks. Ingenious, right? So don’t bother installing it, 
but feel free to check out the code if you are looking for an example of how to:
<ol>
<li>Use the WordPress Settings API to add an option to an existing Settings page;</li>
<li>Use the WordPress AJAX API in conjunction with your plugin options;</li>
<li>Over-engineer a solution to a problem that has already been solved.</li>
</ol>
Enjoy! 🙂

Rewrite Flush Button

Adds a "Flush Rewrite Rules" button to WP-Admin > Settings > Permalinks.

Simple Search Rewrite vs Rewrite Flush Button