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Linux Fundamentals 'Cheat Sheet'

A basic overview of Linux and DevOps Commands

Amelia Gianoli 2026-2-25

Linux & DevOps Command Reference

A handy reference for file management, system monitoring, networking, containers, CI/CD, and more.

File and Directory Management

Command Description
ls List files
ls -la Detailed list including hidden files
cd /path Change directory
pwd Show current directory
mkdir dir Create directory
rm file Remove file
rm -r dir Remove directory recursively
cp src dest Copy file
mv src dest Move/rename file

File Viewing and Editing

Command Description
cat file View file contents
less file Scroll through file
head file First 10 lines
tail file Last 10 lines
tail -f file Follow log output
nano file Edit file
vim file Edit file (advanced)

Permissions and Ownership

Command Description
chmod 755 file Change permissions
chown user:group file Change owner
umask 022 Default permission mask

System Monitoring

Command Description
top Live process view
htop Enhanced process viewer
ps aux List all processes
free -h Memory usage
df -h Disk usage
du -sh * Directory sizes
uptime Load averages

Networking

Command Description
ip addr Show IP addresses
ip link Show interfaces
ip route Show routing table
ping host Test connectivity
curl url HTTP request
wget url Download file
ss -tulpn Show listening ports
traceroute host Trace network path

Services and Systemd

Command Description
systemctl status service Check service status
systemctl start service Start service
systemctl stop service Stop service
systemctl restart service Restart service
systemctl enable service Enable at boot
journalctl -u service View service logs

Package Management

Debian/Ubuntu

Command Description
apt update Update package lists
apt install pkg Install package
apt remove pkg Remove package

RHEL/CentOS/Fedora

Command Description
dnf install pkg Install package
dnf remove pkg Remove package

Users and Groups

Command Description
useradd user Add a user
passwd user Set user password
usermod -aG group user Add user to group
groups user List groups for user

Archiving and Compression

Command Description
tar -czvf file.tar.gz dir Create archive
tar -xzvf file.tar.gz Extract archive
zip file.zip file Zip file
unzip file.zip Unzip file

SSH and File Transfer

Command Description
ssh user@host Remote login
scp file user@host:/path Copy to remote
rsync -av src dest Sync directories

Processes and Jobs

Command Description
kill PID Kill process
kill -9 PID Force kill process
jobs List background jobs
bg Resume job in background
fg Bring job to foreground

Docker (DevOps Essential)

Command Description
docker ps List running containers
docker ps -a List all containers (including stopped)
docker images Show available images
docker pull <image> Download image
docker run <image> Run container from image
docker run -it <image> sh Interactive shell in container
docker stop <container> Stop container
docker start <container> Start container
docker rm <container> Remove container
docker rmi <image> Remove image
docker logs <container> View logs
docker exec -it <container> sh Execute shell inside container
docker build -t name . Build image from Dockerfile
docker-compose up -d Start services
docker-compose down Stop services

Git (DevOps Essential)

Command Description
git clone <repo-url> Clone repository
git status Show changes
git add . Stage all changes
git commit -m "msg" Commit changes
git push Push commits
git pull Fetch & merge
git checkout <branch> Switch branch
git checkout -b <branch> Create & switch branch
git merge <branch> Merge branch
git fetch Download updates
git diff Show file differences
git log --oneline --graph Visual commit history
git stash Save uncommitted changes
git stash pop Restore stashed changes
git reset --hard <commit> Reset branch (destructive)

Kubernetes

Command Description
kubectl get pods List pods
kubectl get svc List services
kubectl get nodes List cluster nodes
kubectl describe pod <pod> Pod details
kubectl logs <pod> Pod logs
kubectl exec -it <pod> -- sh Open shell inside pod
kubectl apply -f file.yaml Apply manifest
kubectl delete -f file.yaml Delete resources
kubectl port-forward pod 8080:80 Forward local port
kubectl rollout status deploy/<name> Check rollout
kubectl rollout undo deploy/<name> Rollback deployment
kubectl scale deploy/<name> --replicas=3 Scale deployment
kubectl top pod Pod resource usage
kubectl config get-contexts List contexts
kubectl config use-context <ctx> Switch context

CI/CD Commands

General Pipeline Utilities

Command Description
curl -X POST <url> Trigger remote pipeline
chmod +x script.sh Make script executable
sh script.sh Run script
env List environment variables
export VAR=value Set environment variable

GitHub Actions

Command Description
gh workflow list List workflows
gh workflow run <name> Trigger workflow
gh run list List recent runs
gh run view <id> View logs

GitLab CI/CD

Command Description
gitlab-runner register Register runner
gitlab-runner run Start runner
gitlab-runner verify Verify runner
gitlab-runner exec shell job Run CI job locally

Jenkins

Command Description
jenkins-cli build <job> Trigger job
jenkins-cli list-jobs List jobs
jenkins-cli console <job> View console output
jenkins-cli disable-job <job> Disable job
jenkins-cli enable-job <job> Enable job

Docker in CI/CD

Command Description
docker build -t app . Build image
docker push app Push image
docker login Authenticate
docker-compose -f file up -d Start multi-service apps

Kubernetes in CI/CD

Command Description
kubectl apply -f file.yaml Deploy manifests
kubectl rollout status deploy/name Wait for rollout
kubectl set image deploy/name container=image Update container image