DevOps Engineer Playbook: Practical Commands for Everyday Use

Welcome to the ultimate "Cheat Sheet" for DevOps Engineers. Whether you are a beginner just starting or a professional who needs a quick reminder, this guide covers the most essential commands for Linux, Git, Docker, Kubernetes, and Terraform.

We have selected the Top 25+ commands for each tool that you will actually use in a real job. No fluff, just practical commands.

Linux is the operating system of the cloud. You cannot survive in DevOps without mastering the terminal.

Command	Use Case (Simple English)
ls -la	List all files, including hidden ones, with details.
pwd	Show me "Print Working Directory" (Where am I?).
cd ..	Go back one folder level.
mkdir folder_name	Create a new folder (directory).
touch file.txt	Create an empty file.
cp file1 file2	Copy file1 to file2.
mv file1 folder/	Move a file into a folder.
rm -rf folder/	Force delete a folder and everything inside it (Careful!).
cat file.txt	Show the content of a file on the screen.
tail -f log.txt	Watch the end of a file in real-time (Great for logs).
grep "error" file.txt	Search for the word "error" inside a file.
chmod 777 file.sh	Give full permissions (Read, Write, Execute) to everyone.
chown user:group file	Change who owns the file.
ps aux	Show all running processes (programs).
top	Show CPU and Memory usage in real-time (Task Manager).
kill 1234	Stop a process using its ID (PID).
df -h	Check disk space (Is your hard drive full?).
free -m	Check how much RAM memory is free.
tar -czvf backup.tar.gz folder/	Compress a folder into a zip/tar file.
curl http://google.com	Test if a website is reachable from the terminal.
wget link.zip	Download a file from the internet.
ping 8.8.8.8	Check if you are connected to the internet.
history	Show the list of commands you typed previously.
sudo su	Switch to the Administrator (Root) user.
systemctl restart nginx	Restart a service (like a web server).

Git helps teams collaborate on code. It is the "Save Game" button for developers.

Command	Use Case (Simple English)
git init	Start a new Git repository in this folder.
git clone [url]	Download a project from GitHub to your computer.
git status	Check which files have been changed.
git add .	Select ALL changed files to be saved.
git commit -m "msg"	Save the selected files with a message.
git push origin main	Upload your saved changes to GitHub.
git pull	Download the latest changes from GitHub.
git branch	List all branches (versions) of your code.
git checkout -b new-feature	Create and switch to a new branch.
git checkout main	Switch back to the main branch.
git merge feature	Combine the 'feature' branch into the current branch.
git diff	Show exactly what lines of code changed.
git log	Show history of all commits (saves).
git reset --hard	Delete all unsaved changes (Dangerous!).
git stash	Temporarily hide changes to work on something else.
git stash pop	Bring back the hidden changes.
git remote -v	Show the URL of the GitHub repository.
git fetch	Check for updates without downloading them yet.
git revert [commit_id]	Undo a specific save without deleting history.
git tag v1.0	Label a specific point in history as "v1.0".
git config --global user.name "Me"	Set your name for Git.
git branch -d feature	Delete a branch you don't need anymore.
git show [commit_id]	See details of a specific save.
git blame file.txt	See who wrote each line of code (Good for debugging).
git clean -fd	Remove untracked files from the folder.

Docker packages applications into containers so they run anywhere.

Command	Use Case (Simple English)
docker version	Check if Docker is installed and running.
docker build -t app:v1 .	Build an image from a Dockerfile.
docker images	List all images stored on your computer.
docker run -d -p 80:80 nginx	Start a container (Nginx) in background on port 80.
docker ps	Show only running containers.
docker ps -a	Show ALL containers (running and stopped).
docker stop [id]	Gracefully stop a running container.
docker kill [id]	Forcefully stop a container instantly.
docker rm [id]	Delete a stopped container.
docker rmi [image]	Delete an image to save space.
docker logs [id]	See what the container is printing (Debugging).
docker exec -it [id] bash	Log inside a running container to type commands.
docker login	Log in to Docker Hub.
docker push user/app:v1	Upload your image to Docker Hub.
docker pull nginx	Download an image from the internet.
docker network ls	List all networks.
docker volume ls	List all storage volumes.
docker system prune	Delete all unused data (Clean up junk).
docker inspect [id]	View detailed technical info about a container.
docker stats	Live view of CPU/RAM usage of containers.
docker-compose up -d	Start multiple containers defined in a compose file.
docker-compose down	Stop and delete all containers from compose.
docker cp file [id]:/path	Copy a file from your PC into a container.
docker history [image]	See how an image was built layer by layer.
docker tag old:v1 new:v2	Rename or re-tag an image.

Kubernetes manages Docker containers at a massive scale.

Command	Use Case (Simple English)
kubectl get nodes	Check the health of the servers (cluster nodes).
kubectl get pods	List all running pods (containers).
kubectl get svc	List Services (Network endpoints).
kubectl get deploy	List Deployments (App managers).
kubectl describe pod [name]	Detailed info about why a pod crashed.
kubectl logs [pod_name]	Read the logs of a specific pod.
kubectl apply -f file.yaml	Create or update resources from a file.
kubectl delete -f file.yaml	Delete everything defined in that file.
kubectl delete pod [name]	Delete a specific pod (It usually restarts).
kubectl exec -it [pod] -- bash	Log inside a pod to run commands.
kubectl scale deploy app --replicas=5	Increase the number of app copies to 5.
kubectl get all	Show pods, services, deployments all at once.
kubectl get pods -o wide	Show pods with extra info like IP Address.
kubectl get namespaces	List all virtual clusters (namespaces).
kubectl config current-context	Check which cluster you are connected to.
kubectl port-forward pod 8080:80	Access a pod on your local computer port 8080.
kubectl rollout status deploy/app	Check if an update finished successfully.
kubectl rollout undo deploy/app	Rollback to the previous version (Emergency).
kubectl top nodes	Check CPU/Memory usage of servers.
kubectl top pods	Check CPU/Memory usage of apps.
kubectl create ns [name]	Create a new namespace.
kubectl edit svc [name]	Edit the configuration live in a text editor.
kubectl cluster-info	Show IP addresses of master and services.
kubectl events	Show recent cluster events (Warnings/Errors).
kubectl explain pod	Documentation about what a "Pod" is.

Terraform allows you to build cloud infrastructure using code.

Command	Use Case (Simple English)
terraform init	Download plugins and prepare the folder.
terraform plan	Show what will happen (Dry Run).
terraform apply	Actually create the infrastructure.
terraform apply --auto-approve	Create it without asking "Are you sure?".
terraform destroy	Delete EVERYTHING.
terraform validate	Check if your code has syntax errors.
terraform fmt	Make your code look pretty (Fix indentation).
terraform show	Show the current state of infrastructure.
terraform output	Show values like IP addresses after creation.
terraform state list	List all resources Terraform is managing.
terraform refresh	Check if the cloud changed outside of Terraform.
terraform graph	Generate a visual graph of your infrastructure.
terraform workspace list	List different environments (dev, prod).
terraform workspace new dev	Create a new environment named 'dev'.
terraform workspace select dev	Switch to the 'dev' environment.
terraform taint [resource]	Mark a resource as broken to force recreation.
terraform untaint [resource]	Unmark the resource.
terraform import [id]	Bring an existing cloud resource into Terraform.
terraform console	Open an interactive shell to test logic.
terraform version	Check installed version.
terraform providers	List plugins (AWS, Azure) being used.
terraform login	Login to Terraform Cloud.
terraform get	Download modules.
terraform plan -out=tfplan	Save the plan to a file.
terraform force-unlock [id]	Unlock the state if it got stuck.