administering-linux

# Linux Administration

Comprehensive Linux system administration for managing servers, deploying applications, and troubleshooting production issues in modern cloud-native environments.

## Purpose

This skill teaches fundamental and intermediate Linux administration for DevOps engineers, SREs, backend developers, and platform engineers. Focus on systemd-based distributions (Ubuntu, RHEL, Debian, Fedora) covering service management, process monitoring, filesystem operations, user administration, performance tuning, log analysis, and network configuration.

Modern infrastructure requires solid Linux fundamentals even with containerization. Container hosts run Linux, Kubernetes nodes need optimization, and troubleshooting production issues requires understanding systemd, processes, and logs.

**Not Covered:**
- Advanced networking (BGP, OSPF) - see `network-architecture` skill
- Deep security hardening (compliance, pentesting) - see `security-hardening` skill
- Configuration management at scale (Ansible, Puppet) - see `configuration-management` skill
- Container orchestration - see `kubernetes-operations` skill

## When to Use This Skill

Use when deploying custom applications, troubleshooting slow systems, investigating service failures, optimizing workloads, managing users, configuring SSH, monitoring disk space, scheduling tasks, diagnosing network issues, or applying performance tuning.

## Quick Start

### Essential Commands

**Service Management:**
```bash
systemctl start nginx              # Start service
systemctl stop nginx               # Stop service
systemctl restart nginx            # Restart service
systemctl status nginx             # Check status
systemctl enable nginx             # Enable at boot
journalctl -u nginx -f             # Follow service logs
```

**Process Monitoring:**
```bash
top                                # Interactive process monitor
htop                               # Enhanced process monitor
ps aux | grep process_name         #