mit-pdos/xv6-public — reverse-engineered prompt

Build me a tiny educational Unix style operating system that I can compile and run in QEMU. I want it to feel like a simple teaching version of early Unix, with a kernel written in C, a boot path for x86, a basic console, process creation, memory management, system calls, files, pipes, and a small shell. Include simple user programs like cat, echo, grep, ls, mkdir, rm, wc, kill, and tests so I can see it working.

Keep the code easy to read and close to textbook style rather than production fancy. I should be able to run make, then make qemu, and land in a working shell where I can try the commands and inspect the source to learn how the OS works. Add clear comments where the important kernel pieces connect. If setup depends on modern QEMU or cross compiler details, look up current docs online and make the build instructions simple.