title: bash wildcard n digits
body: <p>So I've got the following files in the tmp directory:</p>
  
  <pre><code> file.0
   file.1
   file.t9
   file.22
   file.4444
  </code></pre>
  
  <p>if I wanted to list only the files that end in '.digits' (0, 1, 22, 4444) but not (t9) I could try and use wildcards such as this: </p>
  
  <pre><code> ls tmp/file.{[0-9],[0-9][0-9],[0-9][0-9][0-9],[0-9][0-9][0-9][0-9]}
  </code></pre>
  
  <p>however I get the following results with the ugly error</p>
  
  <pre><code> ls: cannot access tmp/file.[0-9][0-9][0-9][0-9]: No such file or directory
   file.0
   file.1
   file.22
   file.4444
  </code></pre>
  
  <p>I've also tried using {0..999} but that also results in the same sorts of errors (and a lot more of them). 
  Any clues as how to do this without errors from the experts? </p>