Theory · Linux basics for DevOps

18 min · Module 2 · Theory

How to study this topic

Read the theory below (concepts, bullets, and shell/YAML examples).
Try the Exam pool and Book quizzes in this module.
After each quiz, use Show answer on every question to review.

Linux basics for DevOps

Shell & file operations

DevOps engineers live in the terminal. Master navigation (cd, ls, find), permissions (chmod, chown), and text processing (grep, awk, sed).

Permissions: rwx for user/group/other — least privilege for service accounts.
Processes: ps, top, signals (SIGTERM vs SIGKILL).
systemd: systemctl status/start/restart — how services start on boot.
Logs: journalctl -u myservice -f for live troubleshooting.

Real-world usage

On-call engineers SSH into nodes, inspect disk (df -h), memory, and restart failed units. Automate repetitive tasks with shell scripts and cron/systemd timers.

Shell, YAML & config examples

# Check disk and memory
df -h
free -m

# Service lifecycle
sudo systemctl restart nginx
journalctl -u nginx --since "10 min ago"

# Find large files
find /var/log -type f -size +100M

# Recursive grep in configs
grep -r "Error" /var/log/app/

Hands-on practice: /lab/