Linux is really only just the kernel. [GNU](/aw/os/gnu) is all the userland stuff like `bash`, `ls`, `gcc` and so on.

But messing around with the kernel can be fun and challenging.

## Links
* [Writing a Simple Linux Kernel Module @ sourcerer](https://blog.sourcerer.io/writing-a-simple-linux-kernel-module-d9dc3762c234?gi=832423cbec38) summarised [here](SummaryWritingASimpleLinuxKernelModule1)