title: Find highest numbered filename in a directory where names start with digits
body: <p>I have a directory with files that look like this:</p>
  
  <pre><code>001_something.php  002_something_else.php
  004_xyz.php        005_do_good_to_others.php
  </code></pre>
  
  <p>I ultimately want to create a new, empty PHP file whose name starts with the next number in the series.</p>
  
  <pre><code>LIST=`exec ls $MY_DIR | sed 's/\([0-9]\+\).*/\1/g' | tr '\n' ' '`
  </code></pre>
  
  <p>The preceding code gives me a string like this:</p>
  
  <pre><code>LIST='001 002 004 005 '
  </code></pre>
  
  <p>I want to grab that 005, increment by one, and then use that number to generate the new filename.  How do I do that in BASH?</p>