title: Renaming files in Shell script for loop
body: <p>I run OS X and have multiple photos and started naming them <code>xyz-100.jpg</code>, <code>xyz-101.jpg</code>, <code>xyz-102.jpg</code> up to <code>xyz-402.jpg</code> and now want to rename them by basically reducing the number by 99, making it <code>xyz-1.jpg</code>, <code>xyz-2.jpg</code> up to <code>xyz-303.jpg</code>.</p>
  
  <p>I know I can use the <code>mv</code> command for that, but I don't seem to be able to implement a variable into the filename, such as <code>xyz-$reduced.jpg</code>. How can I properly do that?</p>