title: PHP passthru() returning "sh: 1: svn: not found " error
body: <p>Our university has free hosting on a Linux server, in which I have checked out a SVN project into my local student directory.  While remotely logging into the server, I have no problems adding/committing/etc to my SVN project sandbox on the server.  </p>
  
  <p>I have a PHP script on the same server that makes a <a href="http://php.net/manual/en/function.passthru.php" rel="nofollow noreferrer">passthru</a> call to perform a simple SVN version number command on that sandbox:</p>
  
  <pre><code>&lt;?php
      echo passthru(' 2&gt;&amp;1 cd /nav/to/svnSandbox &amp;&amp; 2&gt;&amp;1 svn --version ');
  ?&gt;
  </code></pre>
  
  <p>The above exec() call fails server-side and outputs </p>
  
  <p>"sh: 1: svn: not found" to the <a href="http://www.cs.uky.edu/~mtlank2/499sholem/stub499.php" rel="nofollow noreferrer">client</a> side.  This implies that SVN isn't installed?  However, it is in fact installed on the server, moreover I can use SVN just fine while I'm logged in.</p>
  
  <p>The following PHP code works correctly:</p>
  
  <pre><code>&lt;?php
      echo passthru('pwd');
  ?&gt;
  </code></pre>
  
  <p>User permissions for the PHP script and the SVN sandbox directory are 755 (I've tried many other variations as well).  I have also read <a href="https://stackoverflow.com/questions/2143006/php-execsvn-commit-is-not-returning-any-errors-nor-working">this</a> link, among many others.</p>
  
  <p>Is a PHP script not granted certain access to server-side SVN commands? </p>
  
  <p>Why can't I make successful SVN exec() calls from my script? Is there an easier way than my code above?</p>
  
  <p>Do server-admins usually have some sort of safeguard on scripts using exec() that I don't know about?</p>