Easiest way to execute server side code via a HTML button click
<p>Whats the easiest way to execute code on a webserver from a <code>HTML</code> button click? For example I would like a <code>Raspberry Pi</code> running <code>Apache</code> to present a webpage with buttons on it, each button should be able to be pressed which then executes a system command on the <code>Pi</code>. The <code>Pi</code> would be running locally so I am not concerned with security etc.</p>

<p>I know very little about web programming and have seen multiple suggestions, e.g. <code>PHP</code> with <code>HTML</code>, <code>jQuery</code> and <code>AJAX</code> but I just need a simple solution.</p>