Clairos Learn

Learn the UNIX command line through interactive lessons.

Practice Linux and Mac terminal basics in an ops lab. Explore lab files, edit with nano, inspect logs, and learn file and security administration.

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learner@clairos:/home/learner $ Unix ops lab: type a command, press Enter

Starter prompts

Use pwd, ls /, and cat /etc/hostname to map the training server.
Create a new folder named lab and use nano lab/incident-notes.txt to save a note.
Use tail -n 3 /var/log/auth.log, then grep denied /var/log/auth.log.
Run ps and systemctl status nginx to inspect the simulated service layer.
Run whoami, id, groups, and ufw status to practice security inspection.
Run nginx -t, df -h, free -h, and uptime to inspect training operations health.
Try echo alpha beta beta | wc to practice a safe pipeline.

Mission board

Map the server

Find your location, list root, and read the training hostname.

80 XP

Build a runbook

Create a lab note, edit it with nano, then read it back.

120 XP

Investigate logs

Tail the auth log and search for denied login attempts.

110 XP

Service check

Inspect training processes and nginx service status.

100 XP

Security posture

Check identity, firewall status, and simulated sudo boundaries.

130 XP

Validate nginx

Read the training site config, search /api/, and run nginx -t.

120 XP

Pipeline practice

Use a safe text pipe and write one local note with redirection.

110 XP

Terminal checkpoint

Confirm path, host, system label, and history.

180 XP

Filesystem checkpoint

Create an archive, list it, hash a file, and search paths.

200 XP

Text pipeline checkpoint

Filter, extract, transform, and count text.

220 XP

Editing checkpoint

Create and verify an operator runbook.

210 XP

Permissions checkpoint

Review SSH key mode, group, and path type.

220 XP

Operations checkpoint

Review process, service, log, and disk signals.

230 XP

Security checkpoint

Resolve SSH config, fingerprint a key, and review firewall state.

240 XP

Shell checkpoint

Use test, tee, chmod, and stat like a script reviewer.

230 XP

Networking checkpoint

Tie addresses, listeners, firewall, and SSH together.

230 XP

Final operator check

Write and hash the final junior-operator marker.

300 XP

Save progress

Your Learn profile.

Save completed lessons, task completions, mission wins, XP, course status, and streaks with your Clairos account. Lab files, nano drafts, command history, and typed commands stay only in this browser.

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Progress sync stores completion IDs, scores, streaks, badges, and game settings. Terminal contents, editor snippets, lab scratch, email, and real names are never published on leaderboards or share cards.

Course categories

Unix Lab lessons, grouped for steady progress.

Move through missions that start with navigation, then build toward editing files, reading logs, permissions, services, and security administration.

0/34 Terminal basics

Orientation, paths, hidden files, and command history.

34 short lessons · 3 checkpoints 0/36 Files and paths

Create, copy, move, remove, and find files.

36 short lessons · 2 checkpoints 0/38 Text and logs

Read files, search logs, and use text pipelines.

38 short lessons · 4 checkpoints 0/27 Nano and editing

Use simulated nano, edit config copies, and verify saved files.

27 short lessons · 3 checkpoints 0/33 Permissions and users

Modes, owners, groups, and sensitive file review.

33 short lessons · 4 checkpoints 0/36 Server operations

Processes, services, nginx validation, and capacity signals.

36 short lessons · 2 checkpoints 0/35 Security administration

Identity, sudo boundaries, SSH hardening, firewall rules, and review notes.

35 short lessons · 7 checkpoints 0/31 Shell scripting

Script reading, safe guards, text helpers, logging, and review habits.

31 short lessons · 5 checkpoints 0/26 Networking

Addresses, routes, listeners, firewall context, DNS files, and SSH dry runs.

26 short lessons · 2 checkpoints 0/20 Package/process ops

Package metadata, package logs, process snapshots, and signal language.

20 short lessons · 4 checkpoints 0/26 Troubleshooting

A repeatable triage loop across resources, logs, services, network, and packages.

26 short lessons · 2 checkpoints 0/18 Capstone labs

Integrated junior-operator reviews that combine evidence, notes, and validation.

18 short lessons · 18 checkpoints

Browse all lessons

Sandbox objectives

An ops lab you can actually poke.

The mission board turns practice into a small game loop: run, inspect, verify, and reset.

Map the server

Find your location, list root, and read the training hostname.

80 XP

Build a runbook

Create a lab note, edit it with nano, then read it back.

120 XP

Investigate logs

Tail the auth log and search for denied login attempts.

110 XP

Service check

Inspect training processes and nginx service status.

100 XP

Security posture

Check identity, firewall status, and simulated sudo boundaries.

130 XP

Validate nginx

Read the training site config, search /api/, and run nginx -t.

120 XP

Pipeline practice

Use a safe text pipe and write one local note with redirection.

110 XP

Terminal checkpoint

Confirm path, host, system label, and history.

180 XP

Filesystem checkpoint

Create an archive, list it, hash a file, and search paths.

200 XP

Text pipeline checkpoint

Filter, extract, transform, and count text.

220 XP

Editing checkpoint

Create and verify an operator runbook.

210 XP

Permissions checkpoint

Review SSH key mode, group, and path type.

220 XP

Operations checkpoint

Review process, service, log, and disk signals.

230 XP

Security checkpoint

Resolve SSH config, fingerprint a key, and review firewall state.

240 XP

Shell checkpoint

Use test, tee, chmod, and stat like a script reviewer.

230 XP

Networking checkpoint

Tie addresses, listeners, firewall, and SSH together.

230 XP

Final operator check

Write and hash the final junior-operator marker.

300 XP

Reference

Small commands, clear jobs.

These are the first tools learners will practice in the training lab.

help

Show the command list.

pwd

Print the current working directory.

ls [-la] [path]

List lab files and folders.

cd [path]

Change directories inside the lab filesystem.

man <command>

Read a short educational manual page.

which <command>

Locate command paths.

type <command>

Explain whether a command is built in or found on the simulated PATH.

env

Inspect a simulated environment.

uname|hostname|date

Inspect simulated host identity and time.

echo <text>

Print text or write lab notes with >.

printf <text>

Print formatted training text.

mkdir <name>

Create a folder.

touch <file>

Create an empty file.

nano <file>

Open a simulated nano editor.

cat <file>

Print text file contents.

less <file>

Page through a file.

head|tail [-n N] <file>

Read the beginning or end of a file.

grep [-i] <text> <file>

Find literal text inside a file.

awk '{print $N}' <file>

Print a whitespace-delimited field.

sed s/old/new/ <file>

Preview simple text substitutions.

cut -d <char> -f <n>

Extract delimited fields from text.

tr a-z A-Z

Transform piped text case.

tee <file>

Write piped text to a lab file and keep it on screen.

xargs echo|basename

Turn piped words into safe command arguments.

wc [-l] <file>

Count lines, words, and characters.

sort|uniq

Practice simple text pipelines.

diff <left> <right>

Compare two lab text files.

sha256sum <file>

Print a deterministic training checksum.

find [path] [-name text]

Search lab filesystem paths.

file <path>

Identify a simulated file, directory, link, or text format.

realpath <path>

Resolve a path to its canonical simulated location.

mktemp [-d] [template]

Create a bounded temporary file or directory inside the training lab.

nl [file]

Number lines from a file or supported text pipeline.

comm <left> <right>

Compare two sorted text files line by line.

basename|dirname <path>

Split paths into file and directory parts.

readlink <link>

Inspect a simulated symbolic link target.

test -e|-f|-d <path>

Check path type in a training-friendly way.

tar -cf|-tf <archive>

Create and list training archives.

ln -s <target> <link>

Create a simulated symbolic link.

cp <src> <dst>

Copy a file.

mv <src> <dst>

Move or rename a file.

rm <file>

Remove one lab file with safeguards.

chmod <mode> <path>

Change a simulated numeric permission mode.

chown <user:group> <path>

Change simulated owner/group labels.

chgrp <group> <path>

Change a simulated file group label.

stat <path>

Show lab file details.

whoami|id|groups

Inspect the learner account.

ps

Show training server processes.

top|pgrep|kill

Inspect simulated process health and signals.

lsof

Show simulated files and sockets opened by services.

systemctl status <service>

Inspect simulated service status.

journalctl -u <service>

Read simulated service journal entries.

nginx -t

Validate training nginx configuration.

ss|ip

Inspect simulated sockets and addresses.

mount|lsblk

Inspect simulated mounts and block devices.

crontab -l

List a simulated learner crontab.

logrotate -d <config>

Dry-run a simulated log rotation config.

launchctl list|print

Inspect simulated macOS service-launch metadata.

plutil -lint <plist>

Validate a simulated macOS plist file.

apt|dpkg|brew

Inspect simulated Linux and macOS package metadata.

ssh|scp|ssh-keygen

Practice SSH inspection and dry-run transfer shapes without network access.

ufw status

Inspect simulated firewall rules.

df|du|free|uptime

Inspect training resource and system health.

history

Show recent commands.

clear

Clear terminal output.

reset

Reset the lab.

Common questions

A clear start, without guesswork.

How long is a UNIX lesson?

Most lessons take about five to ten minutes and finish with observable command output or a saved lab artifact.

Can I skip to advanced UNIX lessons?

Yes. Courses and lessons remain browseable, while the recommended path and checkpoints provide structure for learners who want it.

What will I be able to do after the UNIX track?

The track builds comfort with navigation, files, text, permissions, services, networking, packages, troubleshooting, and incident runbooks.

How does progress work?

Lesson and mission progress is stored locally. A free account can sync completion IDs, XP, streaks, course status, and resume position across sessions.