title: sed insert after ONLY the first line match?
body: <p>Trying to do this:</p>
  
  <pre><code>sed -e '/^MatchMeOnce/i\
  MATCHED'
  </code></pre>
  
  <p>on the example text:</p>
  
  <pre><code>Line1
  Line2
  MatchMeOnce
  Line4
  MatchMeOnce
  Line6
  </code></pre>
  
  <p>How can I get it to only match the very first record occurrence and to <strong>not</strong> match on subsequent lines?</p>
  
  <pre><code>Line1
  Line2
  MATCHED
  Line4
  MatchMeOnce
  Line6
  </code></pre>