Learn › Linux Foundations › Important Files and Paths
cat - a hands-on Linux lab on a real virtual machine.
The Important Files module capstone mission. Survey an unfamiliar server by reading its own key files: the FHS root (ls /), the account list (cat /etc/passwd), the OS identity (cat /etc/os-release), the mount table (cat /etc/fstab), a live kernel file under /proc, and the hardware tree under /sys, all on a real Linux VM. Mission mode: no commands shown, recall required.
You have finished the Important Files module. You can now read a machine by reading its own files. ls / shows the top-level map of the whole system. cat /etc/passwd lists who can log in. cat /etc/os-release names the operating system. cat /etc/fstab shows how the disks are mounted. Files under /proc report what the kernel is doing live, and /sys lays out the hardware.
This is the final run. One real machine you have never seen, six objectives, and every one of them uses a file you already learned to read. Nothing new is introduced here.
This is mission mode. No commands are shown. You read the objective, recall the file and the command that reads it, and type it. That recall is the whole point: it is how surveying an unfamiliar machine becomes instinct. Progress checks itself as you go, and a signal is one click away if you get stuck.
One quick rep in the practice terminal before the real machine boots. Same rules as the mission: the goal is stated, the command is not. If this comes back instantly, you are ready.
You want this machine's own name, the single word it calls itself. It is stored in one small file. Read that file and print its one line.
prompt: student@linuxcamp:~$ answer: cat /etc/hostname output: survey-01 hint: The reading command, then the small file under /etc that holds only the machine name: cat /etc/hostname
That one line, survey-01, is the name this example machine happens to carry. Your machine prints its own name instead. The value varies from box to box; the move, read the file, is the same everywhere.
That move came from memory, not from a copy button. Good. The mission asks for that same recall six more times, on six different files.
Boot the machine below and take the console. Six objectives: survey the top-level map, read who can log in, read what operating system it is, read how it mounts its disks, read a live figure from the kernel, and explore the hardware tree. No commands shown, progress checks itself as you type.
Practice Operation Know Your Machine in a real Linux terminal at The Linux Camp. Progress is verified automatically as you type commands on the machine.