title: Shell script to create directories
body: <p>I'm trying to create a simple shell script for recursively creating directories inside a list of directories.</p>
  
  <p>I have the next file structure:
  A directory called v_79, containing a list of "dirs" (from dir_0 to dir_210), and inside each of them there are several directories called ENSG00000??????, where '?' stands for a character between [0-9]. </p>
  
  <p>I would like to create a directory called "my_dir" inside every one of the ENSG00000????? dirs.</p>
  
  <p>I know how to create a directory once being inside each of the dir_XX 's,   </p>
  
  <pre><code>    for i in ENSG00000??????; do mkdir $i/my_dir; done
  </code></pre>
  
  <p>but I don't know how to create the directory that I need, in the v_79 directory.</p>