I am obsessed with "The Linux Programming Interface" by Michael Kerrisk. I highly recommend this book if you want to level up your C programming skills and knowledge of Unix operating systems (specially portability and Linux). It might not exactly fit your description, but I still would recommend it. I feel like my C skills have gone from medium to pro, since reading most of the book. One really gets a good grasp of what syscalls exist, what they do and how to properly use them to produce secure and portable code.
It is not written following a single project, but there are many different "applications" in the different chapters, for example, at the end you will be able to program a stand-alone back end TCP server with the examples from the book.
> One really gets a good grasp of what syscalls exist, what they do and how to properly use them to produce secure and portable code.
Yes! The book really exposes all that hidden fun stuff that the system libraries abstract away from us. When I was a beginner I hated not understanding how they worked.
On Linux it's also theoretically possible to make system calls from any language. The binary interface is stable and really simple. Wish more languages had compiler support for this calling convention.
