title: Python match string if it does not start with X
body: <p>I want to search for a file called "AcroTray.exe" on my disk. The program should print a warning <strong>if the file is located in a directory other than "Distillr"</strong>.
  I used the following Syntax to perform the negative match</p>
  
  <pre><code>(?!Distillr)
  </code></pre>
  
  <p>The problem is that although I use the "!" it always produces a MATCH. I tried to figure out the problem using IPython but failed. 
  This is what I tried: </p>
  
  <pre><code>import re
  
  filePath = "C:\Distillr\AcroTray.exe"
  
  if re.search(r'(?!Distillr)\\AcroTray\.exe', filePath):
      print "MATCH"
  </code></pre>
  
  <p>It prints a MATCH.
  What is wrong with my regex?</p>
  
  <p>I would like to get a match on:</p>
  
  <pre><code>C:\SomeDir\AcroTray.exe
  </code></pre>
  
  <p>But not on:</p>
  
  <pre><code>C:\Distillr\AcroTray.exe
  </code></pre>