title: php exec and shell_exec not working
body: <p>I want to run an exe file on my server and return the output to the browser screen.
  The exe file takes a input file and then returns data on the screen.</p>
  
  <p>Why is this code not working?</p>
  
  <pre><code>$output = shell_exec('myprogram &lt; INP.DAT');
  echo "&lt;pre&gt;" . var_export($output, TRUE) ."&lt;/pre&gt;\\n";
  </code></pre>
  
  <p>It displays "NULL" on the browser screen. I have also tried exec(). There it returns "Array()".</p>