title: How to rename a directory in a specific way. BASH
body: <p>I have a directory with a name <strong>20190606_151020</strong>. I want to rename it in <strong>files_2019-06-06_15-10-20</strong>. In the future I won't know the current directory name, but it will be the only directory there, and I also know that I need to make a prefix <strong>files_</strong> and after <strong>2019</strong> should be a <strong>-</strong>.</p>
  
  <p>How could I do it in a BASH script?</p>
  
  <p>I am very bad in working with strings in bash:(</p>