Practical Red Hat notes

Red Hat

General Red Hat Enterprise Linux notes for commands, logs, systemd, networking, storage, CUPS, Veritas, tcpdump and troubleshooting.

Choose a topic below.
Every page is written as a practical beginner-friendly guide.

Useful commands for daily admin checks.

Journalctl, log files and error checking.

Services, status, restart, enable and troubleshooting.

IP, routes, ports, DNS and connection checks.

Disks, partitions, LVM and filesystem checks.

Inode usage, old file listing and safe housekeeping.

Mounts, findmnt, fstab and troubleshooting.

General non-Veritas disk expansion notes.

Cluster/Veritas-aware disk expansion flow.

Cluster checks and safe read-only commands.

Rlink DCM mode checks and escalation flow.

VVR/VRAS service checks and restart notes.

Swap checks and expansion notes.

Users, SSH access, keys and login checks.

Printer creation, deletion and troubleshooting.

What zombies are and how to investigate them.

Packet capture examples and safe usage.

Script notes and admin automation reminders.

General troubleshooting cases and patterns.