The latest articles on DEV Community by Richard Blundell (@richard_blundell_b83fe6e6). https://dev.to/richard_blundell_b83fe6e6 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4101699%2F7cd5ebfe-8860-4dfa-a149-c910625e7463.jpg https://dev.to/richard_blundell_b83fe6e6 en Richard Blundell Sun, 30 Aug 2026 17:52:45 +0000 https://dev.to/richard_blundell_b83fe6e6/hands-on-linux-challenges-on-a-real-throwaway-vm-not-a-quiz-51bh https://dev.to/richard_blundell_b83fe6e6/hands-on-linux-challenges-on-a-real-throwaway-vm-not-a-quiz-51bh <p>Every Linux tutorial I've ever read tells you <em>about</em> a command. None of them hand you a real, broken box and say "fix it." So I built one that does: <strong><a href="https://tmpfs.tech" rel="noopener noreferrer">tmpfs.tech</a></strong> — hands-on Linux and open-source challenges that run on a live, throwaway VM you actually control, right in your browser.</p> <h2> How it works </h2> <ul> <li>Pick a challenge → you get a real Linux session in an <strong>in-browser terminal</strong> (or SSH).</li> <li>The task is a genuine scenario, not a quiz: repair broken nginx, write an nftables ruleset, debug a failing systemd unit, fix a storage mount, eradicate cron-based persistence after a breach.</li> <li>The VM is <strong>ephemeral</strong> — spun up just for you, torn down when you finish. Nothing touches your own machine.</li> <li>Your work is <strong>graded automatically</strong> against the actual system state, so a pass means you really fixed it.</li> </ul> <h2> What's in it </h2> <p>Hundreds of challenges across sysadmin, networking, firewall, systemd, security, web/deploy, bash, storage, Kubernetes, plus offensive and IR tracks.</p> <ul> <li> <strong>Offensive Lab</strong> — local privilege-escalation CTF (SUID/sudo/passwd misconfigs).</li> <li> <strong>Defense &amp; IR</strong> — evict rogue UID-0 accounts, kill systemd/cron persistence, attribute a breach from auth.log.</li> </ul> <h2> A few things I'm proud of </h2> <ul> <li> <strong>Zero signup to start.</strong> Guest play works the moment you land.</li> <li> <strong>Truly isolated.</strong> Each session is its own VM, no internet egress, auto-reaped on idle.</li> <li> <strong>A skill ladder, not a syllabus.</strong> A rating recommends the next challenge by difficulty gap.</li> </ul> <p>I'd genuinely love feedback on the challenge design — which tracks feel right, what's missing, and what you'd want to learn-by-breaking next.</p> <p>Try it here: <strong><a href="https://tmpfs.tech" rel="noopener noreferrer">https://tmpfs.tech</a></strong></p> linux devops sysadmin opensource