// LINUX TROUBLESHOOTING TRAINER

Fix broken Linux servers.
Right in your browser.

A real Debian Linux boots inside your browser. Each scenario hands you a deliberately broken server — investigate and repair it in a real shell, then hit Check for automatic grading. Whatever you break stays inside your browser tab. (UI is currently Japanese.)

▶ START TRAINING FOR FREE No install, no sign-up. Desktop recommended.

user@debian: ~

$ systemctl status nginx

● nginx.service — failed (Result: exit-code)

$ journalctl -u nginx | tail -1

[emerg] open() "/etc/nginx/nginx.conf" failed (13: Permission denied)

$ chmod 644 /etc/nginx/nginx.conf

$ systemctl restart nginx ✔ CHECK PASSED

20+Scenarios (growing)

6Categories

3Difficulty levels

$0Free forever, no ads

// SCREENSHOTS

The real thing

Challenge screen — terminal and mission panel — Challenge screen — a real terminal on the left; mission, grading, hints, and the model solution on the right.

Scenario list screen — Scenario list — filter by difficulty and category. Progress is tracked.

Scenario detail screen — Detail screen — review the situation and expected commands before launching.

// HOW_IT_WORKS

How training works

[01]

Pick a scenario

Filter by three difficulty levels (easy / medium / hard) and category. Start with easy.

[02]

The VM boots, then breaks

Once Debian boots in your browser, the scenario deliberately sabotages the server.

[03]

Investigate & repair

Track down the cause with ls, grep, chmod, ps and fix it. Staged hints if you get stuck.

[04]

Automatic grading

Hit Check to be graded on the final state. Any fix counts. Clear time is recorded.

// CATEGORIES

Break it. Fix it. Get stronger.

▶ START TRAINING NOW

Fix broken Linux servers.Right in your browser.