title: How Extract columns to free command
body: <p>I execute the command <code>free -mo</code> in linux and my output is:</p>
  
  <pre><code>             total       used       free     shared    buffers     cached
  Mem:         64401      33265      31135          0        667      15455
  Swap:         4099          0       4099
  </code></pre>
  
  <p>But i need the output:</p>
  
  <pre><code>             total       used       free
  Mem:         64401      33265      31135
  Swap:         4099          0       4099
  </code></pre>
  
  <p>I intended to use <code>free -mo | awk '{print $1,$2,$3,$4}'</code> but my result is:</p>
  
  <pre><code>total used free shared
  Mem: 64401 33268 31132
  Swap: 4099 0 4099
  </code></pre>
  
  <p>I appreciate your help .</p>