title: Delete files which has the same prefix
body: <pre><code>$prefix = 'something_prefix';
  unlink($prefix.'.*');
  </code></pre>
  
  <p>the code above is not working, but I see some code like this below works just fine</p>
  
  <pre><code>unlink('*.jpg');
  </code></pre>
  
  <p>why? I am wonder is this going to work?</p>
  
  <pre><code>unlink('*.*');
  </code></pre>
  
  <p>how to delete the files which they begin with the same string? like this</p>
  
  <pre><code>same123.jpg
  sametoo.png
  samexxx.gif
  </code></pre>
  
  <p>they all begins with the string "same" but ends with different extension, how to do this?</p>
  
  <p>I alread have a cheap way to do this, but I wonder if there is any better solution?</p>