Cheatsheet

3 frequency levels:

• daily — you type these every day, learn them by heart. If you know these, you’ll be fine.
• occasional — useful regularly, you’ll come back here to look them up when needed.
• rarely — you’ll need these once or twice, mostly for setup or cleanup.

Words between <angle brackets> are placeholders — replace them with your own value. Example: git checkout -b <branch> → git checkout -b feature/login

Git

Command	Description	Frequency
git status	See the current state	daily
git add .	Stage everything	daily
git commit -m "<message>"	Commit	daily
git push	Push to the remote	daily
git pull	Pull from the remote	daily
git checkout -b <branch>	Create and switch to a branch	daily
git log --oneline	Compact history	occasional
git merge <branch>	Merge a branch	occasional
git init	Initialize a repo	rarely
git branch <branch>	Create a branch (without switching to it)	rarely

Linux

Command	Description	Frequency
ls -la	List everything (including hidden files)	daily
cd <path>	Move to a directory	daily
cat <file>	Read a file	daily
mkdir -p <path>	Create directories recursively	daily
grep -r "<text>" <directory>/	Search for text	daily
sudo apt update && sudo apt install -y <package>	Install a package (e.g. curl, git)	daily
pwd	Show current directory	occasional
nano <file>	Edit a file in the terminal	occasional
rm -r <directory>	Delete (recursive)	occasional
cp -r <source> <destination>	Copy (recursive)	occasional
mv <source> <destination>	Move / rename	occasional
chmod 755 <file>	Change permissions	occasional
export <VAR_NAME>="<value>"	Set an environment variable	occasional
ps aux	List processes	occasional
kill <PID>	Kill a process (PID = number shown by ps aux)	occasional
find . -name "*.py"	Search for files	rarely
chown <user>:<group> <file>	Change the owner	rarely
systemctl start/stop/status <service>	Manage a service (e.g. nginx, docker)	rarely
whoami	Show current user	rarely
printenv	List environment variables	rarely
journalctl -u <service>	View logs for a service	rarely

Network

Command	Description	Frequency
curl <URL>	HTTP request (e.g. curl http://localhost:8000/api/tasks)	daily
ss -tlnp	Open ports	occasional
ping <host>	Test connectivity (e.g. ping google.com)	occasional
curl -I <URL>	View headers	occasional
dig +short <domain>	Resolve a DNS (e.g. dig +short google.com)	rarely
wget <URL>	Download a file	rarely
hostname -I	View your private IP	rarely
curl ifconfig.me	View your public IP	rarely
traceroute <host>	Network path	rarely
sudo ufw allow <port>	Open a port (e.g. sudo ufw allow 8000)	rarely
sudo ufw enable	Enable the firewall	rarely
sudo ufw status	View the rules	rarely

HTTP Methods

Method	What it does	Example
GET	Read a resource	curl http://localhost:8000/api/tasks
POST	Create a resource	curl -X POST -H "Content-Type: application/json" -d '{"title":"..."}' http://localhost:8000/api/tasks
PATCH	Update an existing resource	curl -X PATCH http://localhost:8000/api/tasks/1
PUT	Update an existing resource	(not used in this project)
DELETE	Delete	curl -X DELETE http://localhost:8000/api/tasks/1

PATCH vs PUT: to keep it simple, both are used to update data that already exists. The technical difference: PATCH only modifies the fields you send, PUT replaces the entire resource. In practice, many APIs use one or the other interchangeably. In this course we use PATCH — if you see PUT elsewhere, just think of it as the same idea.

Docker

Command	Description	Frequency
docker compose up -d --build	Start with Compose	daily
docker compose down	Stop everything	daily
docker compose ps	View service status	daily
docker compose logs -f	Logs for all services	daily
docker ps	Running containers	daily
docker logs -f <container>	Follow a container’s logs	daily
docker exec -it <container> bash	Enter a container	occasional
docker build -t <name>:<tag> .	Build an image (e.g. docker build -t my-app:1.0 .)	occasional
docker stop <container>	Stop a container	occasional
docker rm <container>	Remove the container	occasional
docker ps -a	All containers (including stopped ones)	occasional
docker run -d -p <host_port>:<container_port> --name <name> <image>	Run a container without Compose	rarely
docker rmi <image>	Remove the image	rarely
docker pull <image>	Download an image (e.g. docker pull postgres:16)	rarely
docker images	List local images	rarely
docker system df	View disk space used by Docker	rarely
docker system prune -a	Clean up unused images/containers	rarely

Bun (frontend)

Command	Description	Frequency
bun install	Install dependencies	daily
bun run dev	Start the dev server	daily
bun run build	Build for production	occasional
bunx oxlint .	Run the linter	occasional

Bun replaces npm + Node.js. The equivalent npm commands: npm install, npm run dev, npx oxlint .

uv (Python backend)

Command	Description	Frequency
uv sync	Install dependencies	daily
uv run uvicorn main:app --reload	Start the backend server	daily
uv run pytest	Run the tests	daily
uv run ruff check .	Run the linter	occasional
uv add <package>	Add a dependency (e.g. uv add fastapi)	rarely

uv replaces pip + venv. The equivalent commands: pip install -r requirements.txt, python -m pytest

GitHub Actions

# Minimal structure
name: CI
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "Hello CI"

Concept	Syntax
Secret	${{ secrets.<SECRET_NAME> }}
Dependency between jobs	needs: <job_name>
Condition	if: github.ref == 'refs/heads/main'

AWS CLI

Command	Description	Frequency
aws ec2 describe-instances	List instances	daily
aws ec2 stop-instances --instance-ids <ID>	Stop (e.g. --instance-ids i-0abc123)	daily
aws ec2 start-instances --instance-ids <ID>	Start	daily
aws s3 cp <file> s3://<bucket>/	Upload	occasional
aws s3 ls s3://<bucket>/	List bucket contents	occasional
aws ec2 terminate-instances --instance-ids <ID>	Permanently delete	occasional
aws configure	Configure credentials	rarely
aws s3 mb s3://<bucket>	Create a bucket	rarely
aws rds describe-db-instances	List RDS databases	rarely
aws rds delete-db-instance --db-instance-identifier <ID> --skip-final-snapshot	Delete an RDS database	rarely
aws lambda list-functions	List Lambda functions	rarely
aws lambda invoke --function-name <NAME> output.json	Invoke a Lambda	rarely
aws lambda delete-function --function-name <NAME>	Delete a Lambda	rarely

Terraform

Command	Description	Frequency
terraform plan	Preview	daily
terraform apply	Apply	daily
terraform init	Initialize (download providers)	occasional
terraform destroy	Delete everything	occasional
terraform fmt	Format the code	occasional
terraform validate	Check the syntax	rarely
terraform state list	View managed resources	rarely

Ansible

Command	Description	Frequency
ansible-playbook -i <inventory> <playbook>.yml	Run a playbook	daily
ansible -i <inventory> <hosts> -m ping	Test the connection	occasional
ansible-playbook -i <inventory> <playbook>.yml --check	Dry run	occasional
ansible-vault encrypt <file>	Encrypt a file	rarely

Kubernetes (kubectl)

Command	Description	Frequency
kubectl get pods	List pods	daily
kubectl get services	List services	daily
kubectl logs <pod>	View logs	daily
kubectl apply -f <file>.yml	Apply a config	daily
kubectl describe pod <pod>	Pod details	occasional
kubectl get deployments	List deployments	occasional
kubectl delete -f <file>.yml	Delete	occasional
kubectl scale deployment <name> --replicas=<N>	Scale (e.g. --replicas=3)	occasional
kubectl rollout status deployment/<name>	Track a deployment	rarely
kubectl get namespaces	List namespaces	rarely
kubectl set image deployment/<name> <container>=<image>:<tag>	Update the image	rarely
minikube start	Start the local cluster	rarely
minikube stop	Stop the local cluster	rarely
minikube image load <image>	Load a local image into minikube	rarely
minikube service <name> --url	Get a service’s URL	rarely

Monitoring

Command / URL	Description	Frequency
http://localhost:9090	Prometheus UI	daily
http://localhost:3001	Grafana UI	daily
curl http://localhost:8000/metrics	View raw metrics	occasional
rate(<metric>[1m])	Rate per second (PromQL)	rarely
histogram_quantile(0.95, ...)	95th percentile (PromQL)	rarely
docker compose up -d (with prometheus.yml)	Start Prometheus + Grafana	rarely