title: how to change extended file attributes of files on mac?
body: <p>I had some iOS projects in my macbook,one day I copied them to my pc which is based on windows system, then some day I copied them back to my macbook and I found the projects can not run.
  I Opened one of the projects with Xcode, it says "builde successfully",but the app can not be deployed on the iPhone Simulator even if the Simulator is running!?!?!?! Then I check the files using "ls -l" command and found that the difference between normal Xcode project files and the new created Xcode project files is just a symbol.</p>
  
  <p>files with problem:</p>
  
  <pre><code>    drwx------+ 49 dingvimer  staff   1.6K 
  </code></pre>
  
  <p>normal file：</p>
  
  <pre><code>    drwx------@ 60 dingvimer  staff   2.0K
  </code></pre>
  
  <p>How can I change that '+' symbol to '@' and get the project run normally?</p>
  
  <p>I will appreciate your kindness of helping me to figure it out (^-^).</p>