title: Linux bash: how to replace 2 words in a file from bash command line
body: <p>I need to replace 2 words in a file from Bash command line, for example:
  fileA.txt</p>
  
  <pre><code>xxxx AA BB xxx 
  </code></pre>
  
  <p>I need to replace "AA BB" from Bash command line with "CC DD", so the file would become: </p>
  
  <pre><code>xxxx CC DD xxx
  </code></pre>
  
  <p>Thanks for your help!</p>