Cross the wall between your code and the kernel.
In this interactive Linux lesson from Stencel Academy you don't just read — you type real commands like strace ls and watch the machine respond on a live, animated map. It is part of the free How Linux Works course.
Builds on: Pipes & Redirection.
strace -c ls — Summarize syscall counts and time.strace -e trace=openat ls — Filter to just the syscalls you care about.cat /proc/self/status — /proc is the kernel answering questions.strace -e openat cat /etc/shadow — A denied trap: the kernel refuses at the gate.