title: Append to a file in Go
body: <p>So I can read from a local file like so:</p>
  
  <pre><code>data, error := ioutil.ReadFile(name)
  </code></pre>
  
  <p>And I can write to a local file</p>
  
  <pre><code>ioutil.WriteFile(filename, content, permission)
  </code></pre>
  
  <p>But how can I append to a file? Is there a built in method?</p>