title: Get Monday and Sunday etc.. for a week for any date as parameter in Unix
body: <p>How to get the date of Monday and Sunday in a week for a date?</p>
  
  <p>This gives date for 'last' monday:</p>
  
  <pre><code>date -dlast-monday +%Y%m%d
  </code></pre>
  
  <p><strong>I want to pass a date as parameter</strong> to find the Monday and Sunday for that week. Basically, I want to get Sunday and Monday for a week, <strong>for ANY date, NOT only for last monday</strong>.</p>