From your first command to running real servers.
Short, hands-on lessons that build on each other. Every one has a practice terminal right in the page, with missions to complete, and shows how it's done on both big Linux families: Rocky/RHEL and Ubuntu/Debian.
- 10
- learning paths
- 73
- hands-on lessons
- ~35 h
- of practice
- 2
- Linux families, side by side
The road map
The paths build on each other, but you don't have to do them all. Start at 1, then follow what you enjoy.
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1Start
New to Linux? Begin here, then keep going.
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2Level up
Run real servers, and keep your work safe in git.
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3Pick a direction
Build and ship software, or keep it running. Do one, or both.
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4Go deeper
Specialise: automate whole fleets, or take it all to the cloud.
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✦Any time
Useful from your first week.
How every lesson works
10 to 45 minutes each. Read a little, then try it yourself.
Learn by doing
A short explanation, then the practice terminal right below it. Missions tick off as you complete them, and you can't break anything: Reset gives you a fresh server.
Both families, side by side
Rocky/RHEL and Ubuntu/Debian next to each other, so you learn what's the same everywhere and what trips people up. Use the Show switch to see only the one you use.
See how far you've come
A quick quiz at the end of each lesson, a tick when you're done, and a certificate when you finish a path. Your progress is saved in this browser.
Where should I start?
Find the line that sounds like you.
Teaching a class, or your own kids? The teacher guide has lesson plans, mission walkthroughs and quiz answer keys.
All learning paths
Each path ends with its own certificate.
1Start New to Linux? Begin here, then keep going.
Linux Basics · Start here
Never used Linux? Start here: the terminal, SSH, files and folders, permissions, installing software, users and services.
Linux Basics 2 · Everyday skills
The next steps after Linux Basics: vim, wildcards, jobs, your machine’s hardware, archives, updates, other ways to install software, and SELinux vs AppArmor.
2Level up Run real servers, and keep your work safe in git.
Linux Sysadmin · Run real servers
Run real servers: networking and security tools, logs, cron, processes, disks, backups, deploying apps and shell scripting.
3Pick a direction Build and ship software, or keep it running. Do one, or both.
Linux DevOps · Ship it, automate it
Package apps as containers, test every change automatically, describe servers as code, and deploy without drama.
4Go deeper Specialise: automate whole fleets, or take it all to the cloud.
Ansible in depth · Automation at scale
Beyond first steps: variables and handlers, reusable roles, secrets with Vault, rolling updates across a fleet, and testing your automation.
AWS basics · Linux in the cloud
Launch Linux servers in the cloud from the command line: networks, servers, storage, load balancers, DNS and alarms, and keep the bill at zero while you learn.
Security basics · Defend your own server
Keep your servers safe: lock down SSH, firewalls in depth, audit and scan your own machines, spot trouble in the logs, find weak permissions, check nothing was changed, and serve your site over HTTPS.
✦Any time Useful from your first week.
All lessons
73 short lessons in 10 paths, about 35 hours in total. Do them in order, or jump to whatever you need.
Linux Basics · Start here
Unit 1 · Getting in
What even is Linux?
Kernels, distros, and the two big families you will meet everywhere.
02Meet the terminal
Prompts, commands, options — reading the screen like a pro.
03Connecting with SSH
Log in to a computer that lives somewhere else.
04SSH apps: PuTTY, iTerm2 & friends
Connect from Windows, Mac, Chromebook or phone — and install keys by hand.
Unit 2 · Files & folders
Look around: pwd & ls
Where am I, and what is in here? Plus hidden files.
06Moving around: cd
Walk the filesystem. Absolute vs relative paths, ~ and ..
07The filesystem tour
/etc, /usr, /var, /proc, /dev… what every folder is for, Rocky vs Ubuntu.
08Make, copy, move, delete
mkdir, touch, cat, cp, mv and rm — carefully.
09Finding files & links
find, locate, which, whereis — and shortcuts with ln.
10Permissions: who can do what
rwx, chmod, chown, umask — and why /etc/shadow is locked.
Unit 3 · Running the system
Installing software: dnf vs apt
The biggest everyday difference between the two families.
12Root, sudo & su
Superpowers, root shells, and who else is logged in.
13Managing users & groups
useradd vs adduser, passwd, groups, shared folders.
14Services & your first website
systemctl, httpd vs apache2, firewalld vs ufw.
15Services deep dive: systemd & init.d
PID 1, init.d, service, runlevels, unit files — and your own service.
Linux Basics 2 · Everyday skills
Unit 1 · Work faster
Text editors: vim (and nano)
Modes, moving, dd/yy/p, undo, search and :%s, then nano, $EDITOR and sudoedit.
02Wildcards & your first pipes
* ? [ ] and {a,b}, echo before rm, quotes, and pipes into wc, grep, sort and head.
03Jobs: pause, background & bring back
Ctrl+C vs Ctrl+Z, &, jobs, bg, fg, kill %1, nohup and disown.
Unit 2 · Know your system
What’s in this computer?
os-release, uname, lscpu, free, lsblk vs df, lspci, lsusb, dmidecode, and "am I a VM?"
05Archives & compression
gzip, xz, bzip2, tar with z/J/j, zip, the file command, and dodging tarbombs.
06Updates done right
Security updates, needs-restarting and reboot-required, kernels, dnf-automatic and unattended-upgrades.
Linux Sysadmin · Run real servers
Unit 1 · Networking
Unit 2 · Sysadmin toolkit
Text power tools
grep, sed, awk, cut, sort, uniq, wc, xargs, diff — and pipes.
04Logs & troubleshooting
journalctl, /var/log, dmesg — then fix a broken website.
05Scheduling with cron
crontab -e, /etc/crontab, /etc/cron.d, and the classic traps.
06Processes & disk space
ps, top, kill, df, du — and hunt down a hidden crypto-miner.
07Disks & mounting
lsblk, fdisk, mkfs, mount, /etc/fstab — add a new disk.
08Backups: tar, rsync & cron
Archive, compress, copy, restore — then automate it all.
09Deploying your company’s app
Capstone: /opt/cht/ourapp, a service account, systemd, upgrades — and the SELinux trap.
Unit 3 · Shell scripting
Shell skills
history, env, --help, watch, tmux & screen, time zones.
11Capturing output
stdout vs stderr, > 2>&1 /dev/null, tee, here-documents, script and logger.
12Subshells & command substitution
$( ), backticks, $(( )), ( ), { }, <( ) — and why Ubuntu’s /bin/sh says no.
13Shell scripting: if, loops & functions
Tests, if, case, for, while read, functions — and debugging with bash -x.
14POSIX: write once, run anywhere
sh vs bash, dash vs bash, bash-isms and their fixes, shellcheck.
Git · Track & share your work
Linux DevOps · Ship it, automate it
Unit 1 · Build & run
Unit 2 · Automate & ship
CI pipelines: test every push
GitHub Actions workflows, gh run view, ShellCheck — watch CI catch bugs, red to green.
04Infrastructure as code: Ansible first steps
Inventory, ad-hoc commands, facts, playbooks and templates — one playbook for Rocky and Ubuntu.
05Secrets & config: the twelve-factor way
Config in the environment, .env and .gitignore, EnvironmentFile, and rotating a leaked password.
06Deploy strategies: blue-green, rolling & rollback
Apache as a reverse proxy, smoke tests, instant rollback — ship v2 without anyone noticing.
Linux SRE · Keep it up, find out why
Unit 1 · Measure
Performance triage: the 60-second checklist
uptime, vmstat, mpstat, pidstat, iostat, free — find what’s slowing a server.
02SLIs, SLOs, SLAs & KPIs: measuring reliability
The nines, error budgets, burn rate and percentiles — measured from a real log with awk.
03Monitoring & alerting with Prometheus
node_exporter, Prometheus, PromQL and an alert rule that fires — plus the rest of the toolbox.
Unit 2 · Respond & plan
Incidents, on-call & blameless postmortems
Severity, roles, updates, roll back first — then handle a live outage and write the postmortem.
05Limits: cgroups, systemd & the OOM killer
Why the OOM killer shot the wrong process, and how MemoryMax, CPUQuota and OOMScoreAdjust fix it.
06Capacity planning & load testing
Find the knee with ab, Little’s Law, headroom and N+1 — then forecast traffic and disk with awk.
Ansible in depth · Automation at scale
Unit 1 · Structure
Unit 2 · Operate
Secrets with Ansible Vault
Encrypt files and strings, vault password files, the vars/vault pattern, no_log.
04Fleets: inventories & rolling updates
Groups of groups, staging vs production, serial, health checks — and a rollout that stops itself.
05Testing & linting your automation
Syntax checks, ansible-lint, idempotence tests, smoke tests and tags.
AI Basics · Use AI wisely
AWS basics · Linux in the cloud
Unit 1 · Foundations
The cloud & AWS: getting started
Regions and AZs, the root user and MFA, installing AWS CLI v2, aws configure and --query.
02IAM: users, groups & policies
Users, groups, roles and JSON policies, access keys and profiles, least privilege.
03VPC: your own network in the cloud
CIDR blocks, subnets, internet gateways, route tables and security groups, built from the CLI.
Unit 2 · Servers & storage
Unit 3 · Scale & names
Load balancers: ELB and ALB
Listeners, target groups and health checks, with security groups chained from the ALB to the servers.
07Auto Scaling: servers that heal and grow
Launch templates, min/max/desired, self-healing, and target tracking under load.
08Route 53: names for your cloud
Hosted zones, NS and SOA, A, CNAME, TXT and alias records, TTLs, checked with dig.
Security basics · Defend your own server
Unit 1 · Mindset & the front door
Think like an attacker
Permission first, threat models, and mapping (then shrinking) your server's attack surface.
02Lock down SSH
Keys only, no root login, the drop-in files that override sshd_config, and never locking yourself out.
03Firewalls in depth
Default deny, SSH only from your network, firewalld zones and rich rules vs ufw rule order, limits and logging.