Linux / CLI / DevOps

Learn how to use jq -S to normalize JSON key order before running diff, allowing you to focus on the actual configuration changes.

Create two types of links in a temporary directory and understand their differences based on inodes and behavior after deleting the original file.

Compare umask 022 and 077 in a temporary directory and observe how new file permissions are determined.

Safely create a temporary Unix domain socket in /tmp and observe how the path acts as an endpoint for communication on the same host. This also helps in understanding PHP-FPM .sock files.

Learn how to check TCP listening ports and their associated processes in Ubuntu using ss. We also break down how to read 127.0.0.1, 0.0.0.0, and [::], and how permissions affect process displays.

This article outlines a safe sequence for testing configurations with nginx -t before reloading Nginx, and using nginx -T to inspect the entire loaded configuration only when necessary.

Combine curl and jq on Ubuntu to extract only the necessary fields from a JSON API response. We will use the GitHub public Repository API as an example.

Don't just stop at systemctl status when troubleshooting Ubuntu service failures. Follow a step-by-step investigation procedure through unit definitions, states, processes, and journals, preserving diagnostic info before restarting.

Let's build a Bash script that mechanically masks sensitive information into **** before passing configuration files to AI. We will organize the process without modifying the original file, including permission control, automated checks, and visual inspection.

This article is a technical explanation and implementation example created using AI. Although the published code and pro...