The kernel primitives, init systems, and tooling behind the world's most-deployed OS.
Trace Linux from Torvalds' 1991 announcement and early licensing through distributions, maintainership, Git and today's release process.
A complete walkthrough encrypting a disk or partition with LUKS, from initial setup through mounting it automatically (with a key file) at boot.
A complete walkthrough from raw disks to a mounted, resizable logical volume — physical volumes, volume groups, and logical volumes explained as you build them.
A practical toolkit for watching CPU, memory, disk, and network usage live — going beyond top to actually find what's causing a resource problem.
A complete, working nftables ruleset for a typical server — default-deny inbound, stateful connection tracking, and a handful of explicit allowed services.
A complete walkthrough generating an SSH key pair, deploying it correctly, and disabling password authentication safely — without locking yourself out.
Using strace to see exactly which system calls a misbehaving program makes — often the fastest way to diagnose a problem with no useful logs.
A complete, working example converting a nightly backup cron job into a properly supervised systemd timer, with logging and failure visibility cron never gave you.
Build, inspect, sign, load and remove a minimal out-of-tree Linux module inside a disposable VM with matching kbuild artifacts and safe rollback.
Compare SELinux label policy and AppArmor profiles through enforcement, logging, safe policy changes, containers and a denial-first audit workflow.