How should I prepare for low-level programming and eventually contributing to Linux?

For low-level programming, networking, and eventual Linux work, C and Linux are a solid starting point. Learn C thoroughly enough to understand pointers, memory management, structs, function pointers, compilation and linking, stack versus heap behavior, and debugging with tools such as gdb and sanitizers. At the same time, become comfortable using Linux: the command line, processes, files, permissions, pipes, signals, system calls, and basic shell scripting. Build small projects instead of only reading tutorials—a simple shell, TCP or UDP client and server, HTTP server, socket-based chat program, memory allocator, multithreaded application, or file-indexing tool would all be useful. Study networking fundamentals like TCP/IP, DNS, HTTP, routing, packets, and ports, and use a packet analyzer to see what is happening. After that foundation, start reading Unix and kernel internals and look for small, well-defined contributions such as documentation, tests, or straightforward bug fixes. The reality check is that kernel development is a difficult, long-term path, but you can learn a lot through interesting systems projects before making a kernel contribution. Don’t wait until you feel you have completely mastered C—learn a concept, use it, get stuck, and investigate the problem.

C is a good fit for understanding how operating systems and networking software work, but C++ and Rust are also worth exploring once you have the fundamentals. Pick real projects, study existing code, and improve or extend programs rather than focusing only on tutorials. Forking a project and finding a small issue to fix can teach you how practical open-source development works.