Try Bruce Molay's Understanding UNIX/LINUX Programming: A Guide to Theory and Practice. It teaches us various Linux/Unix concepts like signal, threads, file I/

Try Bruce Molay's Understanding UNIX/LINUX Programming: A Guide to Theory and Practice. It teaches us various Linux/Unix concepts like signal, threads, file I/O, socket, etc. On some chapters, we'll be guided to re-implement various built-in tools like who, ls, sh, pwd. Very interesting from developer point of view.