LFCA 131 🐧 LFCA – Cheatsheet
The Linux Foundation Certified IT Associate (LFCA) is a pre-professional certification for people entering IT or considering a career in system administration or engineering. It validates breadth across fundamental IT concepts—Linux, system administration, cloud computing, security, DevOps, and project management—rather than depth in any single area. The exam is 90 minutes, multiple-choice, and covers six domains with fixed weights. The domain weights shifted in the September 2025 update: System Administration Fundamentals rose to 30%, while Linux Fundamentals dropped to 16% and DevOps fell to 12% . The cheatsheet below follows the current published weights.
Key point: The LFCA is a breadth exam. You do not need to be an expert in any one domain, but you need working familiarity with each. System Administration is the largest domain at 30%—prioritize it. The exam tests recall of commands and concepts, not hands-on troubleshooting depth.
Exam Domains and Weights (Post-September 2025)
| Domain | Weight | Core Topics |
|---|---|---|
| System Administration Fundamentals | 30% | Users, permissions, networking, troubleshooting, disaster recovery |
| Cloud Computing Fundamentals | 18% | Service models, deployment models, budgeting, availability |
| Linux Fundamentals | 16% | OS concepts, command line |
| Security Fundamentals | 14% | Data security, compliance |
| DevOps Fundamentals | 12% | Git, containers, DevOps basics |
| IT Project Management Fundamentals | 10% | Architecture, functional analysis, open source licensing |
The September 2025 update added “Best Practices” and “Disaster Recovery” to System Administration, and “IT Project Management Fundamentals” replaced the older “Supporting Applications and Developers” domain . Older study materials may reflect the pre-2025 weights (Linux 20%, SysAdmin 20%, Cloud 20%, Security 16%, DevOps 16%, Supporting Apps 8%) . Use the current weights for prioritization.
Linux Fundamentals Commands
| Command | Purpose | Exam Note |
|---|---|---|
pwd | Print working directory | Orientation command |
ls -la | List all files with details | -a shows hidden, -l long format |
cd /path | Change directory | cd ~ returns home |
cat file | Display entire file | For small files |
less file | Page through file | q to quit, /pattern to search |
head -n 20 file | First 20 lines | Default is 10 |
tail -f log | Follow live log | -f follows appends |
grep pattern file | Search text | -r recursive, -i case-insensitive |
find /path -name "*.txt" | Find by criteria | -type f for files only |
wc -l file | Count lines | -w words, -c bytes |
cp -r dir1 dir2 | Copy recursively | -i prompts before overwrite |
mv old new | Move or rename | |
rm -rf dir | Remove recursively | Caution: irreversible |
mkdir -p a/b/c | Create nested directories | -p creates parents |
Filesystem Hierarchy Standard (FHS): /etc configuration, /home user homes, /var variable data (logs), /bin essential binaries, /usr user programs, /tmp temporary files .
System Administration
User management:
| Command | Purpose |
|---|---|
useradd -m -s /bin/bash user | Create user with home and shell |
usermod -aG group user | Add to supplementary group (-a append!) |
userdel -r user | Delete user and home |
passwd user | Set password |
id user | Show UID/GID and groups |
whoami | Current username |
Permissions: chmod 755 file = rwxr-xr-x. r=4, w=2, x=1. chown user:group file changes ownership .
Disk and memory:
| Command | Shows |
|---|---|
df -h | Free/used space per filesystem (human-readable) |
du -sh /path | Total size of a directory |
free -h | Memory usage |
lsblk | Block devices |
Process management:
| Command | Purpose |
|---|---|
ps aux | List all processes |
top / htop | Interactive process monitor |
kill PID | Terminate by PID |
pkill -u user | Kill all user processes |
nice -n 10 cmd | Start with lower priority |
systemd (service management):
| Command | Purpose |
|---|---|
systemctl start svc | Start now |
systemctl enable --now svc | Start now + at boot |
systemctl status svc | Check state |
systemctl daemon-reload | Reload after unit file changes |
journalctl -u svc | Service logs |
journalctl -f | Follow logs live |
Scheduling: crontab -e edits user crontab. Format: min hour dom month dow command. */5 * * * * /path/script.sh runs every 5 minutes. at 02:30 tomorrow schedules a one-time job .
Networking commands:
| Command | Purpose |
|---|---|
ip addr | Show IP addresses |
ip route | Show routing table |
ss -tuln | Listening TCP/UDP sockets (numeric) |
ping host | Test connectivity |
dig domain / nslookup domain | DNS lookup |
curl -I url | HTTP headers only |
ssh user@host | Remote shell |
scp file user@host:/path | Secure copy over SSH |
Cloud Computing Fundamentals
Service models:
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps | Virtualization, hardware | EC2, Azure VMs, GCE |
| PaaS | Apps, data | OS, runtime, hardware | Heroku, App Engine |
| SaaS | Nothing | Everything | Gmail, Salesforce |
| FaaS | Function code | Runtime, scaling | Lambda, Cloud Functions |
Deployment models: Public (shared infrastructure), Private (dedicated), Hybrid (combination), Multi-cloud (multiple providers) .
Virtualization vs containers: VMs run a full OS per instance (gigabytes, minutes to boot). Containers share the host kernel (megabytes, seconds to boot) .
Cloud concepts: Availability (uptime guarantees/SLAs), elasticity (automatic scaling), budgeting (cost monitoring, reserved instances vs on-demand).
Security Fundamentals
| Concept | Key Point |
|---|---|
| Least privilege | Grant only permissions required for the task |
| Encryption at rest | LUKS for disk encryption on Linux |
| Encryption in transit | TLS/HTTPS, SSH |
| Firewall (Ubuntu) | ufw is the default front-end |
| SSH restriction | AllowUsers admin in /etc/ssh/sshd_config |
| Compliance | GDPR (personal data), data anonymization |
DevOps Fundamentals
| Concept | Key Command/Note |
|---|---|
| Git branch + switch | git checkout -b feature creates and switches |
| CI/CD stages | Build → Test → Deploy |
| Containers | Docker images, docker run, docker ps |
| Infrastructure as Code | Declarative configuration (Terraform, Ansible) |
IT Project Management Fundamentals
| Topic | Key Point |
|---|---|
| Software architecture | Microservices = independently deployable services |
| Open source licenses | GPL (copyleft: derivatives must be GPL), MIT/Apache/BSD (permissive) |
| Functional analysis | Requirements gathering, user stories |
| Project management | Agile, Scrum, sprint review |
Common Pitfalls
| Pitfall | Fix |
|---|---|
| Studying old domain weights | Use post-September 2025: SysAdmin 30%, Linux 16% |
Confusing df and du | df = filesystem free space; du = directory size |
Forgetting -a in usermod -aG | Without -a, user is removed from other groups |
tail vs tail -f | -f follows live updates; essential for logs |
| Assuming LFCA requires deep expertise | It is breadth-focused, entry-level multiple-choice |
Missing systemctl daemon-reload | Required after unit file changes |
Visual: Domain Weights (Current)
┌──────────────────────────────────────────────┐
│ LFCA EXAM WEIGHTS (POST-SEP 2025) │
│ │
│ System Administration ████████████ 30% │
│ Cloud Computing ███████ 18% │
│ Linux Fundamentals ██████ 16% │
│ Security █████ 14% │
│ DevOps ████ 12% │
│ IT Project Management ████ 10% │
│ │
│ SysAdmin is the largest domain. │
│ Prioritize users, permissions, systemd, │
│ networking, and troubleshooting. │
│ │
└──────────────────────────────────────────────┘Summary
| Area | Key Takeaway |
|---|---|
| Exam format | 90 min, multiple-choice, entry-level breadth |
| Largest domain | System Administration (30%) |
| Linux commands | pwd, ls, grep, find, df, du, tail -f |
| User management | useradd, usermod -aG, userdel -r |
| Permissions | chmod 755, chown user:group |
| systemd | systemctl enable --now, journalctl -u |
| Networking | ip addr, ss -tuln, ssh, scp |
| Cloud models | IaaS/PaaS/SaaS/FaaS; Public/Private/Hybrid |
| Security | Least privilege, LUKS, ufw, GDPR |
| DevOps | Git branch, CI/CD stages, containers |
| Licensing | GPL (copyleft), MIT/Apache (permissive) |
The LFCA rewards breadth. You do not need to memorize every command flag; you need to recognize what each command does and when to use it. System Administration is the heaviest domain, so spend proportionally more time on users, permissions, systemd, and networking. Cloud concepts are conceptual—know the service models and deployment models. Security and DevOps are smaller but present; do not skip them. The official Linux Foundation training page lists the current competencies, and the September 2025 update is the authoritative source for domain weights .
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