Do you know good site?

Do you know any good web site about system programming?

I've been looking for sites about C-programming in UNIX environment.. and emulating UNIX command by C..
but there is little about that..

If you know some good abnout that,,
please let me know..

Thanks for helping...

here's one:
http://www.cs.cf.ac.uk/Dave/C/CE.html

remember this one also: http://www.google.com to search for such sites