linux_skill

Overview

This skill teaches practical Linux system administration fundamentals for DevOps and infrastructure work. It covers process management, filesystem operations, permissions, package management, user administration, bash scripting, and system monitoring. The goal is to give hands-on commands, troubleshooting patterns, and recovery steps you can apply immediately.

How this skill works

The skill presents core command patterns and workflows for managing processes, filesystems, packages, users, and services across common distributions. It includes quick-reference commands, a troubleshooting checklist, and recovery procedures for typical failures like out-of-disk or permission errors. Optional and advanced topics expand into LVM, systemd, kernel tuning, and container-friendly cleanup techniques.

When to use it

• Onboard new engineers to Linux administration basics
• Perform daily server maintenance and package updates
• Troubleshoot production incidents (disk, memory, permissions)
• Write or review bash scripts and automation tasks
• Prepare systems for CI/CD pipelines and deployments

Best practices

• Always check distribution-specific package manager (apt vs dnf) before installing
• Prefer graceful process termination (SIGTERM) before using SIGKILL
• Use sudo and least-privilege accounts; verify with id and ls -la
• Keep regular backups and monitor disk usage to avoid out-of-space failures
• Automate repetitive tasks with small, tested bash scripts and version them in source control

Example use cases

• Find and stop a runaway process using ps, top, kill, or pkill
• Fix permission errors by checking ownership and applying chmod/chown or ACLs
• Update and patch servers: apt update && apt upgrade -y or dnf update -y
• Recover from full disk: find large files with du, clean caches and vacuum journalctl
• Add a user and grant sudo: useradd -m -s /bin/bash user; usermod -aG sudo user