Developer Essentials

Developer Essentials Cheatsheets

Quick references for everyday developer tools. Copy-paste ready commands.

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📚 Git Cheatsheet

Basic Commands

# Initialize repo
git init

# Clone repo
git clone 
git clone --depth 1           # Shallow clone (faster)

# Status & info
git status
git log --oneline -n 10
git diff
git diff --staged

Staging & Commits

git add .                           # Stage all
git add -p                          # Stage interactively
git commit -m "message"
git commit --amend                  # Edit last commit
git commit --amend --no-edit        # Keep message

Branches

git branch                          # List branches
git branch -a                       # List all (including remote)
git checkout -b               # Create & switch
git switch                    # Switch branch
git merge 
git rebase 

Push & Pull

git push origin 
git push -u origin          # Set upstream
git pull
git pull --rebase
git fetch origin

Undo & Fix

git restore                   # Discard changes
git restore --staged          # Unstage
git reset HEAD~1                    # Undo last commit (keep changes)
git reset --hard HEAD~1             # Destroy last commit
git stash
git stash pop

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🐳 Docker Cheatsheet

Images

docker images                       # List images
docker pull 
docker build -t  .
docker build -t  -f Dockerfile.dev .
docker rmi 
docker image prune

Containers

docker ps                           # Running containers
docker ps -a                        # All containers
docker run -d -p 8080:80    # Detach + port
docker run -it --rm  bash    # Interactive + remove
docker exec -it  bash
docker logs -f           # Follow logs
docker stop 
docker rm 
docker rm -f             # Force remove

Docker Compose

docker compose up -d
docker compose down
docker compose logs -f
docker compose restart
docker compose build

Cleanup

docker system prune -a              # Remove all unused
docker system df                    # Disk usage

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☸️ Kubernetes (kubectl) Cheatsheet

Context & Config

kubectl config get-contexts
kubectl config use-context 
kubectl cluster-info

Get Resources

kubectl get pods
kubectl get pods -A                 # All namespaces
kubectl get services
kubectl get deployments
kubectl get nodes
kubectl get ns                      # Namespaces
kubectl get all

Describe & Debug

kubectl describe pod 
kubectl logs 
kubectl logs -f                # Follow
kubectl exec -it  -- bash
kubectl top pods                    # Resource usage
kubectl top nodes

Apply & Delete

kubectl apply -f manifest.yaml
kubectl apply -k ./                 # Kustomize
kubectl delete -f manifest.yaml
kubectl delete pod 

Quick Actions

kubectl expose deployment  --port=80 --type=LoadBalancer
kubectl scale deployment  --replicas=3
kubectl rollout restart deployment/

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🔍 jq Cheatsheet (JSON Processor)

Basic Queries

# Identity (pretty print)
jq '.' file.json

# Get field
jq '.name' file.json
jq '.user.name' file.json

# Array index
jq '.[0]' file.json
jq '.[0].name' file.json

Array Operations

# Array length
jq '. | length' file.json

# All items in array
jq '.[]' file.json

# Map - extract field from array
jq '.[].name' file.json
jq '.[] | {name, email}' file.json

# Filter array
jq '.[] | select(.age > 30)' file.json
jq '.[] | select(.status == "active")' file.json

Transformations

# Create new object
jq '{user: .name, email: .contact.email}' file.json

# Add/remove fields
jq '. + {timestamp: now}' file.json
jq 'del(.password)' file.json

Useful Flags

jq -r '.name' file.json             # Raw output (no quotes)
jq -c '.' file.json                 # Compact (one line)
jq -s '.' file1.json file2.json     # Slurp multiple files

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🌐 curl Cheatsheet

Basic Requests

curl https://api.example.com
curl -I https://example.com         # Headers only
curl -v https://example.com         # Verbose

HTTP Methods

curl -X POST https://api.example.com/data
curl -X PUT https://api.example.com/data/1
curl -X DELETE https://api.example.com/data/1

Headers & Body

curl -H "Content-Type: application/json" \
     -H "Authorization: Bearer token" \
     https://api.example.com

curl -X POST -d '{"name":"test"}' \
     -H "Content-Type: application/json" \
     https://api.example.com

curl -X POST --data @file.json https://api.example.com

Output & Download

curl -o output.json https://api.example.com
curl -O https://example.com/file.zip  # Save with original name
curl -L https://example.com           # Follow redirects

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🐧 Linux Essential Commands

File Operations

ls -la                              # List all (including hidden)
cp -r source dest                   # Copy recursive
mv old new                          # Move/rename
rm -rf dir                          # Remove recursive force
mkdir -p path/to/dir                # Create parents too
touch file
chmod 755 file
chown user:group file

Search & Find

grep "pattern" file.txt
grep -r "pattern" .                 # Recursive
grep -i "pattern" file.txt          # Case insensitive
find . -name "*.txt"
find . -type f -size +100M          # Files > 100MB

Process Management

ps aux                              # All processes
top                                 # Interactive process viewer
htop                                # Better top (if installed)
kill -9                        # Force kill
pkill -f process_name

System Info

df -h                               # Disk usage
free -h                             # Memory
uname -a                            # System info
whoami
pwd                                 # Current directory

Text Processing

cat file.txt
head -20 file.txt
tail -f log.txt                     # Follow file
less file.txt
wc -l file.txt                      # Line count
sort file.txt
uniq file.txt

Network

ifconfig / ip addr
netstat -tulpn                      # Listening ports
ss -tulpn                           # Modern netstat
ping example.com
curl ifconfig.me                    # Get public IP
ssh user@host
scp file.txt user@host:/path

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💡 Pro Tips

1. Use man for full documentation
2. Use --help flag on most commands
3. Pipe commands together: ps aux | grep nginx
4. History search: Press Ctrl+R in terminal
5. Aliases save time - add to ~/.bashrc or ~/.zshrc