title: sed more than one number or 'g' in substitute flags
body: <p>When I run my command I get:</p>
  
  <pre><code>sed 's/&lt;?xml version="1.0" encoding="UTF-8"?&gt;//2g' all.xml
  sed: 1: "s/&lt;?xml version="1.0" e ...": more than one number or 'g' in substitute flags
  </code></pre>
  
  <p>How can I fix this? It doesn't make much sense to me. I'm trying to remove all but the first instance of <code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;</code> from a new xml file.</p>