title: Csv: search for String and replace with another string
body: <p>I have a .csv file that contains:</p>
  
  <pre><code> scenario, custom,    master_data
   1,        ${CUSTOM},  A_1
  </code></pre>
  
  <p>I have a string:</p>
  
  <pre><code> a, b, c
  </code></pre>
  
  <p>and I want to replace 'custom' with 'a, b, c'. How can I do that and save to the existing .csv file?  </p>