title: bash script to delete folders with a name_date older than 90 days
body: <p>I have a folder with a large data history</p>
  
  <pre><code>data/
    2010.01.01/
      f1/
      f2/
      ...
    2010.01.02/
      ...
    ...
  </code></pre>
  
  <p>and I would like to have another folder with just the folders that have a name with a date in the last 90 days</p>
  
  <pre><code>data_recent/
    2020.02.28/
      f1/
      f2/
      ...
    ...  
    2020.05.28/
      ...
  </code></pre>
  
  <p>what is the easiest way I can sync the new folders and delete the old ones with a bash script?
  The box is running on centos7</p>