title: mod_rewrite or mod_alias?
body: <p>I have a server, its httpd.conf already has some "<em>RedirectMatch permanent</em>" directives in it.</p>
  
  <p>I'm not that familiar with mod_alias, I've only ever used mod_rewrite.</p>
  
  <p>What's the basic difference?  I don't see a "L" flag in mod_alias to stop processing rules.</p>
  
  <p>Which one should I use for best practices of redirecting from one sub-domain to another?</p>
  
  <p>Can I use both at the same time and will it be obvious which takes precedence?</p>