title: Subtract months from a given date in bash
body: <p>I want to subtract months from a given date.</p>
  
  <pre><code>businessDate='2019-12-31'
  diff=1
  busDate=$(date --date="$businessDate -$diff month" +%Y-%m-%d)
  echo "Date: $busDate"
  </code></pre>
  
  <p>This code returns 2019-12-01 instead of 2019-11-30. Can someone please suggest a solution to get the correct date?</p>