title: change lowercase file names to uppercase with awk ,sed or bash
body: <p>I would like to change lowercase filenames to uppercase with awk/sed/bash</p>
  
  <p>your help would be appreciated</p>
  
  <pre><code>aaaa.txt
  vvjv.txt
  acfg.txt
  </code></pre>
  
  <p>desired output</p>
  
  <pre><code>AAAA.txt
  VVJV.txt
  ACFG.txt
  </code></pre>