title: Why would Textpad ask if you want to use POSIX regular expression syntax?
body: <p>I need to separate out a bunch of image urls from a document in which the images are associated with names like this:</p>
  
  <pre><code>bellpepper = "http://images.com/bellpepper.jpg"
  cabbage = "http://images.com/cabbage.jpg"
  lettuce = "http://images.com/lettuce.jpg"
  pumpkin = "http://images.com/pumpkin.jpg"
  </code></pre>
  
  <p>I want to remove all text except the URLs from the file by deleting the variable name, equals sign and double quotes so I have a new file that is just a list of URLs, one per line.</p>
  
  <p>I've tried <a href="https://stackoverflow.com/questions/1141046/how-to-get-the-inverse-of-a-regular-expression">various ways</a> of identifying the non-URL data using regular expressions in Textpad by checking the "Regular expression" checkbox in the Find dialog window but Textpad doesn't seem to like any of them.</p>
  
  <p>Under </p>
  
  <pre><code>Configure-&gt;Preferences-&gt;Editor
  </code></pre>
  
  <p>there's an option:</p>
  
  <pre><code>"Use POSIX regular expression syntax"
  </code></pre>
  
  <p>As opposed to what? </p>
  
  <p>Is it possible that my problems performing this regex operation have to do with some quirk of Textpad's implementation of regex?</p>