systemd Beyond Services: Units, Targets and Dependencies
systemd manages units, and services are only one kind. Sockets, mounts, targets and slices explained — plus the difference between requiring something and waiting for it, which is behind most…
How Packages and Dependencies Actually Work
What a package contains, how a repository is indexed and trusted, why shared library versions are the real reason dependencies exist, and what mixing sources does to a system.
Containers: What Is Actually Happening
A container is an ordinary Linux process with a restricted view of the system. Namespaces, cgroups and overlay filesystems explained — and the problems that stop being mysterious once you…
What the Kernel Actually Does
Linux is the kernel — not the distribution around it. What lives on each side of the userspace boundary, how to watch a program ask for something, and why an…
Shell History — Stop Retyping Commands
Ctrl+R, history expansion, the readline editing keys worth learning, and the configuration that stops your history vanishing every time you close a terminal.
User Management — useradd, usermod, passwd and chage
Creating accounts, adding someone to a group without wiping the groups they already had, password ageing with chage, and why locking an account beats deleting it.
systemd Timers: Scheduled Jobs That Tell You What Happened
Timer units do what cron does, with proper logging, dependency handling and catch-up after downtime. The syntax, a working example, and when cron is still fine.
dd: Writing Images and Cloning Disks
Write a bootable USB, clone a disk, or destroy the wrong one — dd does exactly what you tell it, without asking. How to use it, and how to check…
Monitoring a Server Without a Full Observability Stack
Find out a service died before your users do — systemd OnFailure alerts, a disk-space check, and external uptime monitoring. No Prometheus, no Grafana, about an hour.
A Reverse Proxy with Automatic TLS
Putting several self-hosted applications behind one domain, each on its own subdomain with a certificate that renews itself — with Caddy, and the Nginx equivalent.