authentication

How to Use journalctl for Systemd Log Analysis on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use journalctl for Systemd Log Analysis on RHEL 9

The Linux kernel’s systemd journal is a structured binary log that stores the output of every service, kernel message, boot sequence, and user session. Unlike traditional text-based syslog, the journal stores metadata alongside each log entry — the unit name, PID, UID, executable path, systemd unit state, and priority level — enabling far more precise […]

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How to Install GitLab Runner on Debian 13 — step-by-step Debian 13 tutorial on Progressive Robot

How to Install GitLab Runner on Debian 13

Introduction This guide explains how to Install GitLab Runner on Debian 13 on Debian 13 Trixie. Debian Trixie uses systemd for service management, nftables as the underlying packet filter (with ufw or iptables front-ends still available), and AppArmor for mandatory access control. Every command is designed for a minimal Debian 13 install with the standard […]

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How to Set Up Basic Authentication in Nginx on Debian 13 — step-by-step Debian 13 tutorial on Progressive Robot

How to Set Up Basic Authentication in Nginx on Debian 13

Introduction Deploying set up basic authentication in nginx on a Debian 13 Trixie machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites You will need […]

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How to Use rsync for Efficient File Synchronisation on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use rsync for Efficient File Synchronisation on RHEL 9

rsync is the Swiss Army knife of file synchronisation for Linux administrators. Unlike scp, which blindly copies every file every time, rsync computes a rolling checksum to identify changed file blocks and transfers only what has changed — making subsequent syncs dramatically faster and less bandwidth-intensive. It preserves file attributes (permissions, ownership, timestamps, ACLs, extended […]

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How to Manage Users and Groups with useradd, groupadd and passwd on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Manage Users and Groups with useradd, groupadd and passwd on RHEL 9

While the earlier tutorial in this series covered the core useradd, usermod, and userdel tools for user lifecycle management, this guide goes deeper into the full toolkit for managing users and groups at scale on RHEL 9: bulk creation, password management with chpasswd, group administration with gpasswd, per-user resource limits with ulimit and /etc/security/limits.conf, user […]

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How to Install VictoriaMetrics on Oracle Linux 10 — step-by-step Oracle Linux 10 tutorial on Progressive Robot

How to Install VictoriaMetrics on Oracle Linux 10

Introduction How to Install VictoriaMetrics on Oracle Linux 10 on Oracle Linux 10 provides administrators with a robust, enterprise-ready workflow that integrates cleanly with systemd, SELinux, firewalld, and the modern AppStream module system. In this tutorial we will walk through every step required, from package installation to verification, so that the resulting configuration is reproducible […]

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How to Configure MariaDB Galera Cluster on Oracle Linux 10 — step-by-step Oracle Linux 10 tutorial on Progressive Robot

How to Configure MariaDB Galera Cluster on Oracle Linux 10

Introduction Setting up configure mariadb galera cluster on oracle linux 10 on a Oracle Linux 10 server is a common task for system administrators, DevOps engineers, and site reliability engineers. This guide explains how to Configure MariaDB Galera Cluster on Oracle Linux 10, with all the commands you need, the SELinux and firewalld considerations to […]

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Common Problems 116588

Ubuntu 24.04 LTS sudo Fails Due to Invalid /etc/sudoers Syntax

šŸ”“ Critical   ā± 5–30 min  Last verified: 3 November 2025 Affected versions: Ubuntu 24.04 LTS šŸ“– ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors […]

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How to Configure Network Namespaces on Debian 13 — step-by-step Debian 13 tutorial on Progressive Robot

How to Configure Network Namespaces on Debian 13

Introduction This guide explains how to Configure Network Namespaces on Debian 13 on Debian 13 Trixie. Debian Trixie uses systemd for service management, nftables as the underlying packet filter (with ufw or iptables front-ends still available), and AppArmor for mandatory access control. Every command is designed for a minimal Debian 13 install with the standard […]

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How to Capture Packets with tcpdump on Debian 13 — step-by-step Debian 13 tutorial on Progressive Robot

How to Capture Packets with tcpdump on Debian 13

Introduction Deploying capture packets with tcpdump on a Debian 13 Trixie machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites You will need a registered […]

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