Linux System Programming
Linux system programming involves using the system call interface to the Linux kernel. The video tutorials are about I/O, inter-process communication, network socket programming, processes and threads, and general system usage.
C is a high level procedural programming language. The videos provide basic C programming concepts, syntax and example programs.
GNU/Linux Command Line
The command line is the basic way of communicating with a computer. The video tutorials explain how to run programs, major options, example command usage and sample outputs.