How would I find the user-agent from the http requests which were made to my website : <p>So a bit of a two part question </p>

<ol>
<li><p>When users make requests to our website where is the information from our http request header stored </p></li>
<li><p>Can you access the user-agent from this (for example googlebot)[Would this be done with a serverside language like ruby/php?]</p></li>
</ol>
