title: overall CPU usage and Memory(RAM) usage in percentage in linux/ubuntu
body: <p>I want to findout overall CPU usage and RAM usage in percentage, but i dint get success</p>
  
  <pre><code>$ command for cpu usage
  4.85%
  
  $ command for memory usage
  15.15%
  </code></pre>
  
  <p>OR</p>
  
  <pre><code>$ command for cpu and mamory usage
  cpu: 4.85%
  mem: 15.15%
  </code></pre>
  
  <p>How can I achieve this? </p>