MANDATORY

Process lifecycle and management (ps, top, kill)
Filesystem hierarchy and operations
File permissions (chmod, chown, ACLs)
Package management (apt, yum, dnf)
User and group administration
Basic bash scripting

OPTIONAL

LVM and disk partitioning
Systemd service management
Log analysis with journalctl

ADVANCED

Kernel parameters and sysctl
SELinux/AppArmor security
Performance profiling

Quick Reference

# Process Management
ps aux | grep [p]rocess          # Find process (avoid grep itself)
kill -15 PID                      # Graceful termination
kill -9 PID                       # Force kill (last resort)
pkill -f pattern                  # Kill by pattern
nohup command &                   # Background immune to hangup

# File Permissions
chmod 755 file                    # rwxr-xr-x
chmod u+x,g+r file               # Symbolic notation
chown -R user:group dir/         # Recursive ownership
setfacl -m u:user:rw file        # Set ACL

# Package Management (Debian/Ubuntu)
apt update && apt upgrade -y
apt install -y package
apt autoremove

# Package Management (RHEL/CentOS)
dnf update -y
dnf install package

# User Management
useradd -m -s /bin/bash user
usermod -aG sudo user
passwd user

# System Info
uname -a                          # Kernel info
cat /etc/os-release              # OS version
free -h                           # Memory usage
df -h                             # Disk usage

Troubleshooting

Common Failures

Symptom	Root Cause	Solution
Permission denied	Insufficient privileges	Use sudo or check ownership
Command not found	Package not installed	Install with apt/dnf
No space left	Disk full	Clean /var/log, docker prune
High load	CPU/IO bottleneck	Use top, iotop

Debug Checklist

Check permissions: id, ls -la
Check disk: df -h, du -sh /*
Check memory: free -h
Check logs: journalctl -xe

Recovery Procedures

Out of Disk Space

Find large files: du -sh /* | sort -rh | head
Clean cache: apt clean
Rotate logs: journalctl --vacuum-size=100M

MANDATORY

OPTIONAL

ADVANCED

Quick Reference

Troubleshooting

Common Failures

Debug Checklist

Recovery Procedures

Out of Disk Space

Resources

Name	Type	Required	Default	Description
distro	string	No	ubuntu	Target distribution
operation	string	Yes	-	Operation category

linux-fundamentals-skill

Linux Fundamentals Skill

Overview

Parameters

Core Topics