C Systems Lab is a free interactive web course that walks through 10 modules of systems programming in C: compilation, pointers, dynamic memory, structs, the preprocessor, file I/O, processes and signals, sockets, concurrency, and a tour below C.

The free course itself is the link. Get the free sample of the PDF by adding "/demo" to the link. Since I don't necessarily like the paywall aspect of it, you may ask me for the complete edition by reaching out via email.

Happy to answer questions about the content or the curriculum design.