DNS Resolution on Linux: dig, nslookup, resolv.conf
How Linux turns names into IP addresses, and how to debug when it goes wrong. The four tools that solve 99% of DNS problems.
-
-
Sockets and Ports: ss Replaces netstat
See exactly what is listening on your machine and what is connected. ss is the modern netstat — faster and more powerful.
-
pacman: The Arch Linux Package Manager
pacman is fast, minimal, and slightly cryptic. Once you memorize the flag combinations, it is the cleanest package manager out there.
-
IP and Routing: The ip Command
The modern ip command replaces ifconfig and route. One tool to inspect addresses, links, routes, and ARP.
-
dnf: The Fedora and Red Hat Package Manager
dnf is the package manager on Fedora, RHEL, Rocky, Alma, and CentOS. Modern, fast, and increasingly capable.
-
apt: The Debian and Ubuntu Package Manager
apt is the package manager on Debian, Ubuntu, and their derivatives. These are the commands you will type every week.
-
Pick Your Package Manager: apt, dnf, pacman
Which package manager you use depends entirely on your distro. The concepts are the same; the commands differ.
-
journalctl: Read Linux System Logs
Every modern Linux system logs to journald. journalctl is how you query those logs — by service, time, severity, anything.
-
systemctl: Start, Stop, Enable, Status
The five systemctl commands you will type 50 times a day. Master these and you control every service on your Linux system.
-
systemd and Unit Files: Write Your Own Service
systemd is the init system on every modern Linux. Writing a unit file is the standard way to make your script start on boot.