title: find matching text and replace next line
body: <p>I'm trying to find a line in a file and replace the next line with a specific value. I tried sed, but it seems to not like the \n. How else can this be done?</p>
  
  <p>The file looks like this:</p>
  
  <pre><code>&lt;key&gt;ConnectionString&lt;/key&gt;
  &lt;string&gt;anything_could_be_here&lt;/string&gt;
  </code></pre>
  
  <p>And I'd like to change it to this</p>
  
  <pre><code>&lt;key&gt;ConnectionString&lt;/key&gt;
  &lt;string&gt;changed_value&lt;/string&gt;
  </code></pre>
  
  <p>Here's what I tried:</p>
  
  <pre><code>sed -i '' "s/&lt;key&gt;ConnectionString&lt;\/key&gt;\n&lt;string&gt;&lt;\/string&gt;/&lt;key&gt;ConnectionString&lt;\/key&gt;\n&lt;string&gt;replaced_text&lt;\/string&gt;/g" /path/to/file
  </code></pre>