title: Dockerfile FROM Instruction
body: <p>The <a href="https://docs.docker.com/engine/reference/builder/#/from" rel="noreferrer">Dockerfile reference</a> says the following about the FROM instruction:</p>
  
  <blockquote>
    <p><code>FROM</code> can appear multiple times within a single <code>Dockerfile</code> in order to create multiple images. Simply make a note of the last image ID output by the commit before each new <code>FROM</code> command.</p>
  </blockquote>
  
  <p>I don't understand what they mean by <em>note the last image ID output by the commit</em>. I'm not really sure I see the point at all in having multiple <code>FROM</code> instructions.</p>
  
  <p>Is there any valid use case of this?</p>