Every Linux tutorial I've ever read tells you about a command. None of them
hand you a real, broken box and say "fix it." So I built one that does:
tmpfs.tech — hands-on Linux & open-source challenges
that run on a live, throwaway VM you actually control, right in your browser.
How it works
- Pick a challenge → you get a real Linux session in an in-browser terminal.
- 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.
- The VM is ephemeral — spun up just for you, torn down when you finish. Nothing touches your own machine.
- Your work is graded automatically against the actual system state, so a pass means you really fixed it.
What's in it
720 challenges across 16 tracks — General Linux, Networking, Firewall, systemd,
Security & TLS, Web & Deploy, Bash & Scripting, Text Processing, Storage & Disk,
Kubernetes — plus two wargame tracks:
- Offensive Lab — local privilege-escalation CTF (capture a root-only flag via SUID/sudo/passwd misconfigs).
-
Defense & IR — evict rogue UID-0 accounts, kill systemd/cron persistence,
and attribute a breach straight from
auth.log.
A few things I'm proud of
- Zero signup to start. Guest play works the moment you land.
- Truly isolated. Each session is its own VM, auto-reaped on idle so nothing runs away.
- A skill ladder, not a syllabus. A Glicko-2 rating tracks your level and recommends the next challenge by difficulty gap — closer to a puzzle feed than a fixed course.
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.
Try it here: https://tmpfs.tech
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