file permission: How to set project permission so that it can be executed by Apache but cannot be accessed by other users?

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http://serverfault.com – I don't know much about permissions in linux, so I need some help here. My web server is in Amazon EC2, and I have a web project that stores in /home/sean directory, and my apache user is sean as well. I know that there is another user ubuntu as well, but I don't want user ubuntu to see the source code. I try to mess around by changing the permissions of the project directory, and I realize that I cannot hide the directory while still make apache be able to execute the project. If I do chmod +x -R . within the directory, user ubuntu can see the directory. If I remove the execution permission, (HowTos)