title: The cloud-init yaml file is not valid due to dynamic variable
body: <p>I'm getting an error with my cloud-init yaml content.
  The command I execute is:</p>
  <pre><code>cloud-init devel schema --config-file test.yaml
  </code></pre>
  <p>And here's the test.yaml file.</p>
  <pre><code>#cloud-config
  ---
  users:
    - default
  runcmd:
    - [ TOKEN=$(echo &quot;Htkdi_8js&quot;) ]
    - [ wget, -O, /tmp/some.sh, &quot;https://some_public_website&quot;, --header=&quot;Authorization: Token $TOKEN&quot; ]
  </code></pre>
  <p>The error is</p>
  <pre><code>Cloud config schema errors: runcmd.1: ['wget', '-O', '/tmp/some.sh', 'https://some_public_website', {'--header=&quot;Authorization': 'Token $TOKEN&quot;'}] is not valid under any of the given schemas
  </code></pre>
  <p>I'm new to cloud-init. Thank you.</p>