Apache Authentication

[jwilliams]

Sort of a noobie Q here, so hopefully it should be easy to anser:

On my next website, I want to integrate the UI to the linux OS as much as possible. in doing so, i would like to authenticate users against system users.

As you may know, these username/passwords are generally kept in /etc/passwd and /etc/shadow (Are there other files like this with different encryption methods?)

How do I write an .htaccess file to authenticate against users in these two files (keeping in mind additional rigor may be necessary for the shadow case)

Also, how would I authenticate users of groups against the linux system, that is to say, is there a /etc/groups type file that i need to think about?

Thanks.

[jledhead]

I think this article http://httpd.apache.org/docs/2.2/howto/auth.html would be a good start and this link
http://www.javascriptkit.com/howto/htaccess.shtml

[jwilliams]

I tried to do this, and quickly realized that user permissions prevent apache from reading /etc/shadow. On second thought, I am uncomfortable with anyone but root reading this file.