title: svn post-commit hook : update only if certain file has changed
body: <p>Okay so I have an SVN repo setup on my server.  I have a post-commit hook setup that updates to a "DEV" folder so that when I commit changes, it automatically pushes to my "DEV" subdomain on my server. </p>
  
  <p>What I need now is an easy way to push it to my "Live" subdomain when I am ready.  The "Live" subdomain is on the same server, and in reality, it would be the same svn update /... command as with the DEV, but to a different path.  </p>
  
  <p>I was thinking I could have a specific file in my repo, and maybe I could just change this file, and then make some sort of condition in my post-commit file to also update to my "live" dir if that specific file has changed.  </p>
  
  <p>But I don't know how to write that code.  Currently my post-commit file looks like this:</p>
  
  <pre><code>#!/bin/sh
  
  REPOS="$1"
  REV="$2"
  
  svn update /var/www/dev/public
  </code></pre>
  
  <p>I need it to basically do this (but with correct syntax, obviously)</p>
  
  <pre><code>#!/bin/sh
  
  REPOS="$1"
  REV="$2"
  
  svn update /var/www/dev/public
  if (pushLive.txt has changed) {
    svn update /var/www/live/public
  }
  </code></pre>
  
  <p>Anybody have any suggestions?  </p>