I'm in the process of setting up a server from a clean CentOS 5 install. What is the best permission structure (users, groups, unix permissions) for running a single instance of apache for multiple users? Ideally, it should satisfy these requirements: Each user's websites are stored in a subdirectory of their home directory. Users can edit files and permissions. Apache can read the websites of all users. No user can read the website files of other users. Bonus question: how to add PHP and/or Perl and/or Ruby to Apache without allowing any users to access any other user's files?