missions
20 handcrafted missions
Each mission teaches one UNIX concept inside a story — but all the teaching happens at the terminal. Progressive difficulty, three-tier hints, and a solve walker mean you can finish every one.
chapter 01
- 01gentle~4m
Awaken
First breath. First keystroke.
- 02gentle~5m
Hidden Things
A dot makes a file shy.
- 03beginner~7m
The Log
Four failures. Then a success.
chapter 02
- 04beginner~6m
Permissions
Read, write, execute — who's allowed?
- 05beginner~10m
Broken Config
A missing dash. A silent node.
- 06beginner~5m
Shortcuts
An arrow that means elsewhere.
- 07beginner~7m
Paper Trail
Two logs. One story.
- 08beginner~5m
Empty Hands
Build the space before you fill it.
chapter 03
- 09intermediate~8m
The Archive
Years of dust. One working key.
- 10intermediate~6m
Two Users
Different names. Different keys.
- 11intermediate~7m
Renaming Ghosts
Give the files their real names.
- 12intermediate~8m
False Twins
A hyphen pretending to be an underscore.
chapter 04
- 13intermediate~8m
Two Logs
Count fails. Name victims.
- 14intermediate~10m
Shared Secret
Three files. Three modes. One passphrase.
- 15intermediate~6m
Needle in Needles
One file in forty holds the note.
- 16intermediate~7m
The Ledger
Columns tell you who did what.
- 17intermediate~6m
Broken Link
An arrow pointing at nothing.
chapter 05
- 18intermediate~6m
The Empty Server
Scaffold a case from scratch.
- 19advanced~4m
Lockdown
Clock's ticking.
- 20advanced~14m
The Long Shift
Everything you've learned. One mission.