title: bash script create multiple directories within directories
body: <p>I want to create a directory structure like this in nix:</p>
  
  <p><code>mkdir -p 1,2,3,4,5,6,7,8,9</code> and within each of these folders I want folders <code>1,2,3,4,5,6,7,8,9</code></p>
  
  <p>I have started to write a simple loop like this (all the way up to folder 2) but this seems inefficient.</p>
  
  <pre><code>#!/usr/bin/env bash   
  for i in 1 2 4 5 6 7 8 9; do mkdir -p 1/{1,2,3,4,5,6,7,8,9} $i, mkdir -p  2/{1,2,3,4,5,6,7,8,9} $2; done
  </code></pre>
  
  <p>Is there a better way of doing it?</p>