I'm assuming you have a FreeBSD box handy. If not then you should :-) If you're just getting started with unix and C I'd say start with /usr/src/bin and /usr/

I'm assuming you have a FreeBSD box handy. If not then you should :-) If you're just getting started with unix and C I'd say start with /usr/src/bin and /usr/src/usr.bin since there are plenty of easy things there like cat, date, etc. Next I'd head over to /usr/src/lib/libc, do a grep for "Chris Torek". Everything he writes is good. Learning low level details about how libc works on whatever platform you're on is always a good thing if you're doing any real C programming. After that it's a matter of taste. Find something that interests you and read that (e.g. if you like kernel stuff head over to /usr/src/sys).