what sources should I read ?
bayareaguy: 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).