title: Joining Line Breaks With Condition in SED
body: <p>I have data that looks like this:</p>
  
  <pre><code>&gt; sq1
  foofoofoobar
  foofoofoo
  &gt; sq2
  quxquxquxbar
  quxquxquxbar
  quxx
  &gt; sq3
  foofoofoobar
  foofoofoo
  &gt; sq4
  foofoofoobar
  foofoo
  </code></pre>
  
  <p>I want to join the lines on the basis of ">sqi" header as cut-off line,
  i.e. yielding:</p>
  
  <pre><code>foofoofoobarfoofoofoo
  quxquxquxbarquxquxquxbarquxx
  foofoofoobarfoofoofoo
  foofoofoobarfoofoo
  </code></pre>
  
  <p>I tried using this <code>sed</code> but fail:</p>
  
  <pre><code>sed '/^S/d;N;s/\n/\t/' 
  </code></pre>
  
  <p>What's the correct way to do it?</p>