Use sed or awk to replace line after match
<p>I'm trying to create a little script that basically uses <code>dig +short</code> to find the <em>IP</em> of a website, and then pipe that to <strong>sed</strong>/<strong>awk</strong>/<strong>grep</strong> to replace a line. This is what the current file looks like:</p>

<pre><code>#Server
123.455.1.456
246.523.56.235
</code></pre>

<p>So, basically, I want to search for the '#Server' line in a text file, and then replace the two lines underneath it with an <em>IP</em> address acquired from <strong>dig</strong>.</p>

<p>I understand some of the syntax of <strong>sed</strong>, but I'm really having trouble figuring out how to replace two lines underneath a match. Any help is much appreciated.</p>