title: Using du to get size of specific sub directories
body: <p>I'm trying to write a script to summarise a bunch of folders. So I have the following structure:</p>
  
  <pre><code>monitor/abc_123 1G
  monitor/abc_213 1G 
  monitor/abc_111 2G
  monitor/bbc_123 2.5G
  </code></pre>
  
  <p>What I need is to issue a command (using du I presume) to summarise the directories prefixed with "abc_"</p>
  
  <p>I've tried the following:</p>
  
  <pre><code>du -sh abc*
  </code></pre>
  
  <p>... but this just gives me a summary for each folder. I need the script to generate the total size of all three directories in this example.</p>
  
  <p>Thanks in advance</p>