Linux /var Real-World Scenario Quiz

Scenario 1 Not answered

You receive an alert: Filesystem /var is 95% full. Which command should you run first to find what is taking space?

sudo rm -rf /var/* sudo du -h /var --max-depth=1 | sort -h sudo gzip -r /var sudo chmod -R 777 /var

Explanation: First investigate the disk usage. The du command with --max-depth=1 shows which first-level folders inside /var are using space. Never delete or compress blindly.

Scenario 2 Not answered

Your web server is working, but /var/log is growing very fast. Which command helps check the total size of /var/log?

sudo du -sh /var/log sudo systemctl delete logs sudo rm -rf /var/log sudo lsblk /var/log

Explanation: sudo du -sh /var/log shows the total size of the log directory in human-readable format.

Scenario 3 Not answered

A DevOps server running Docker has low disk space. You suspect Docker is using too much storage. Where is Docker data commonly stored?

/var/log/docker /var/lib/docker /etc/docker/data /home/docker

Explanation: Docker commonly stores images, containers, layers, volumes, and other runtime data under /var/lib/docker.

Scenario 4 Not answered

Your CI runner has many unused Docker images and stopped containers. Which command should you run first to check Docker disk usage?

docker system df sudo rm -rf /var/lib/docker docker delete all sudo gzip /var/lib/docker

Explanation: docker system df safely shows Docker disk usage before cleanup. After reviewing it, you can decide whether docker system prune is needed.

Scenario 5 Not answered

Your Ubuntu server has a large /var/cache/apt directory. Which command safely cleans the package cache?

sudo apt clean sudo dnf clean all sudo rm -rf /var/cache sudo cache clear apt

Explanation: On Ubuntu/Debian, sudo apt clean safely removes downloaded package cache files.

Scenario 6 Not answered

Your RHEL server has a large /var/cache/dnf directory. Which command should you use to clean package cache?

sudo apt clean sudo dnf clean all sudo dpkg clean sudo rpm --delete-cache

Explanation: On RHEL/Fedora systems, sudo dnf clean all cleans DNF package cache safely.

Scenario 7 Not answered

A MySQL database stores data in /var/lib/mysql. You want to back it up. What is the safest approach?

Run gzip -r /var/lib/mysql while MySQL is running Use mysqldump or stop MySQL before a file-level backup Delete old files from /var/lib/mysql Move /var/lib/mysql to /tmp

Explanation: Database files change while the database is running. Use proper backup tools like mysqldump, or stop the service before taking a file-level backup.

Scenario 8 Not answered

An application is actively writing logs to /var/log/app.log. What is the best practice for compressing logs?

Compress the active log directly with gzip /var/log/app.log Use logrotate to rotate and compress old logs Delete the active log file Change permissions to 777

Explanation: logrotate is the correct tool for managing logs. It rotates active logs and compresses old logs safely.

Scenario 9 Not answered

Apache/NGINX is running, but the website shows a blank or default page. Which common default web root should you check first?

/var/www/html /var/cache/html /var/log/html /etc/www/html

Explanation: /var/www/html is commonly used as the default web root in many Apache and NGINX labs. The exact path still depends on server configuration.

Scenario 10 Not answered

A junior admin suggests running sudo rm -rf /var/* to fix disk space. What should you say?

Good idea, run it quickly It is dangerous and can break the system It only deletes cache files It only removes old logs

Explanation: /var contains logs, databases, Docker data, package manager data, mail, web files, and service state. Deleting everything can seriously damage the system.

Result