Just finished self-studying C with "The C Programming Language, 2nd Ed." by Brian Kernighan and Dennis Ritchie, and am looking for a good follow-up book that can kind of pick up where that book left of - specifically pertaining to programming C under Linux (sockets, threading, IPC, etc.). I did the search thing, but there are so many books (some of them quite expensive) that it is hard to pick one.
I know the Kernighan/Ritchie book is frequently used in C programming courses, so I was kind of curious what schools (and other self-learners) have been using after it?