Linux
The shell, permissions, processes and services.
Linux is taught here in 14 lessons, running from Shell basics and navigation through to Performance triage and troubleshooting. Each lesson takes one topic, shows the working code, and links onward to the next, so the course can be read straight through in order.
| Track | DevOps & Tooling |
| Lessons | 14 |
| Level | Beginner to intermediate |
| Reading time | about 3 hours |
| Prerequisites | Helpful, but not required: Git |
Lessons
- Shell basics and navigationPaths, the commands used every day, and how to read a command line rather than memorizing flags.
- Files and permissionsReading rwx bits, chmod usage without magic numbers, ownership, and finding files quickly.
- Working with textgrep, less, head/tail, pipes and redirection — composing small tools into exactly the answer you need.
- Processes, ports and jobsInspecting what runs, stopping it gracefully, checking which port is busy, and keeping work alive after logout.
- SSH, packages and servicesKey-based login without passwords, copying files safely, installing software, and managing services.
- Users, groups and privilegeAccounts, groups, sudo rules and the safe ways to move between identities without handing out root.
- Installing software across distributionsapt, dnf, pacman, snap and flatpak, repository priorities, and what to do when no package exists.
- Disks, filesystems and mountsBlock devices, partitions, mkfs, fstab entries by UUID, and extending a volume without losing data.
- Networking: addresses, DNS and firewallsInterfaces and routes, DNS resolution, the tools that prove where a connection dies, and firewall rules that do not lock you out.
- Archiving, syncing and backupstar and compression formats, rsync options and semantics, incremental snapshots, and a backup you have actually restored.
- Scheduling work: cron and systemd timersCrontab syntax and its environment traps, then systemd timers with real logging and catch-up behaviour.
- systemd units and reading logsUnit types and dependencies, a service unit you can trust, restart policies, and getting real answers out of journalctl.
- Environment, dotfiles and shell configurationVariables and PATH precedence, which startup file runs when, and keeping dotfiles reproducible across machines.
- Performance triage and troubleshootingA repeatable method for a slow server: load, memory, CPU, disk and I/O, then syscall-level evidence.
More in DevOps & Tooling
Git Docker Kubernetes Nginx CI / CD Bash Scripting Ansible
FAQ
How long does the Linux course take?
It has 14 lessons, about 3 hours of reading. Expect roughly twice that if you type out and run every example.
Do I need prior experience for Linux?
Not strictly. It helps to have read Git first, because some lessons build on it, but every lesson explains its own assumptions.
What should I read after Linux?
Continue with Docker (12 lessons), the next course in DevOps & Tooling.
Last refreshed 2026-09-18.