W3DevOps Module · Linux: The Kernel, the Filesystem and 70 Commands I Actually Use
Every container, VM and CI runner I deploy boots Linux. This is the foundation chapter of my DevOps handbook — architecture, the FHS, streams and redirection, and the 70 commands behind every incident I've debugged.
When I started self-hosting my projects on a Google Cloud VM, the thing that slowed me down was never Docker or Kubernetes — it was Linux. A permission bit on ~/.ssh/authorized_keys, a log file nobody was rotating, a process that kept a port bound after a crash. So the very first track of my W3DevOps handbook is Linux, and this module is that track, split into lessons.
It is written as lab notes: what each piece is, why it matters on a server, and the exact command I run. The screenshots are captures from the course labs I worked through while building the handbook.
What this module covers
- The layered Linux architecture — hardware, kernel, shell, user space — and why containers depend on it
- The Filesystem Hierarchy Standard from a DevOps point of view (
/etc,/var/log,/proc) - stdin / stdout / stderr and the redirection patterns used in cron, systemd and CI
- All 70 commands from the course, grouped by the job they do
Lessons in this module
- Linux Fundamentals for DevOps Engineers — Linux is the bedrock of modern DevOps, cloud infrastructure, containerization (Docker, Kubernetes), and server administration. Every container runs a Linux userland; every cloud VM boots Linux by default.
- All 70 Essential Linux Commands for DevOps — Here is the complete, categorized breakdown of the 70 commands every engineer needs to know when managing Linux virtual machines, containers, and cloud clusters.
- 70 Essential Linux Commands Quick Reference — Use the table below for rapid lookup during server maintenance, shell scripting, or technical interviews.
Start with Lesson 01: Linux Fundamentals for DevOps Engineers — every lesson links to the next, and you can mark each one complete.
How this shows up in my projects
- Quintrix ITSO redeploys by SSH-ing into a Compute Engine VM and running
git reset --hard origin/main && docker compose up -d --build— every one of those steps is a Linux primitive from this post. - The Coolify server behind my side projects needed
chmod 700 ~/.sshandchmod 600 authorized_keysbefore it would validate; SSH silently rejects anything looser. > output.log 2>&1is in almost every background worker I've written, including the CinePrompt render queue.
Next in the series: Docker in production — namespaces, cgroups, layer caching and multi-stage builds.
Keep going: Start the module → · Full course outline · Self Guide
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