title: bash- remove \n every three lines
body: <p>How can I remove newline delimiter from every three lines.
  Example:</p>
  
  <p>input:</p>
  
  <pre><code>1
  name
  John
  2
  family 
  Grady
  3
  Tel
  123456
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>1
  name John
  2
  family Grady
  3
  Tel 123456
  </code></pre>