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…
sudo — Running Commands as Another User
sudo runs one command as another user, normally root, after checking that you are allowed to. The point is not convenience — it is that nobody needs to know the…
rsync — Sync Files and Directories
rsync copies files, but only the parts that changed. On the second run of a large transfer it sends almost nothing, which makes it the right tool for anything you…
vim and nano — Editing Files in a Terminal
Sooner or later you will SSH into a server, type vim or find yourself dropped into it by git commit, and discover that nothing you try makes it stop. This…
Disks and Mounting — lsblk, mount and fstab
Linux does not have drive letters. Every filesystem is grafted onto a single tree at a mount point — a directory that becomes the doorway to that storage. Once that…
Package Management — apt, dnf and pacman
Every distribution installs software from repositories, and every distribution family uses a different command to do it. The concepts are nearly identical; only the spelling changes. This page puts the…
curl and wget — Fetch Things Over HTTP
Both fetch things over HTTP. The difference in practice: curl is for talking to things — APIs, headers, authentication, sending data. wget is for taking things — downloading files, resuming,…
ln — Hard Links and Symbolic Links
Linux has two kinds of link and they are not variations on the same idea — they work at different levels of the filesystem. Understanding the difference takes one paragraph…
Networking Basics — ip, ss, ping and dig
“The network is broken” is four or five different problems wearing the same coat. These commands tell them apart: is there an address, is anything listening, can packets reach the…