Introducing the cmd: Your New Go-To Bookmark for Essential Software Engineering Commands 🔖

# Clear terminal output
clear # List files in the current directory with details
ls -la # Check system stats
df -h
cat /etc/os-release
cat /proc/meminfo
nproc # Working with linux service
systemctl status target_service
systemctl start target_service
systemctl stop target_service
journalctl -u target_service # Change file mode
chmod +x some_file.sh # Change directory owner
chown 0600 /path/to/directory # Create new directory
mkdir -p /path/to/directory # Change directory
cd /path/to/directory # Copy a file or directory
cp source destination # Move or rename a file or directory
mv old-name new-name # Remove a file
rm file-name # Show disk usage of directories and files
du -h --max-depth=1 # Search for a pattern in files
grep -r "pattern" /path/to/search # Display the current directory's path
pwd # History
history # CURL, add '-k' to ignore certificate verification
curl https://abc.example.com # wget - Download a file from a URL
wget http://example.com/file.zip # wget - Download a file and save it with a different name
wget -O newfile.zip http://example.com/file.zip # Check network
netstat -anpt # Check system metric (CPU/RAM/...)
top # Tar
tar -cvf sampleArchive.tar /home/sampleArchive # Extract
tar -xvf sampleArchive.tar
tar -xvf sampleArchive.tar.gz -C /home/ExtractedFiles/

# Generate SSH keys
ssh-keygen -t rsa # SSH to a server using username/password
ssh [email protected] # SSH to a server using key
ssh -i user_key.pem [email protected] # Use locally available keys to authorise logins on a remote machine
ssh-copy-id [email protected]

# Pretty-print JSON data
jq '.' # Extract a specific field from a JSON object
jq '.fieldName' file.json # Filter JSON data by a specific condition
jq 'select(.fieldName == "value")' file.json # Parse JSON from an API response
curl -s http://api.example.com/data | jq '.' # Flatten a nested JSON structure
jq '.[].nestedField' file.json # Format JSON output into a more readable structure
jq '.' file.json | less

# Clone repo via HTTPS
git clone https://github.com/REPO_OWNER/repo.git # Clone repo via SSH
git clone [email protected]:REPO_OWNER/repo.git # Create a new branch
git checkout -b new-branch # Pull the latest changes from the remote repository
git pull origin main # Check the status of your working directory
git status # Add all changes to the staging area
git add . # Commit changes with a message
git commit -m "Your commit message" # View log
git log # Push to remote feature branch
git push origin new-branch # Reset staging area to match the lastest origin commit
git reset origin/main

# List all running containers
docker ps # List all containers (including stopped ones)
docker ps -a # Build an image from a Dockerfile
docker build -t your-image-name . # Run a container from an image
docker run --name container-name your-image-name # Stop a running container
docker stop container-name # Remove a stopped container
docker rm container-name # Remove an image
docker rmi image-name # Show container logs
docker logs container-name # List all Docker images
docker images # Enter a running container's shell
docker exec -it container-name /bin/bash # Cleanup docker (add `-f` flag to force cleanup)
docker system prune ## Docker Compose
# Start up containers as defined in the Docker Compose file
docker compose up # Start up containers in detached mode
docker compose up -d # Stop running containers
docker compose down

# Export KUBECONFIG to access the cluster
export KUBECONFIG=/path/to/kubeconfig.conf # Check nodes
kubectl get nodes # Get all pods in the target namespace
kubectl get pods -n your_namespace # Get all services in the current namespace
kubectl get svc -n your_namespace # Get all resources in all namespace
kubectl get all -A # Describe a pod
kubectl describe pod pod-name # Apply a configuration to a resource by filename or stdin
kubectl apply -f config-file.yaml # Delete resources by filenames, stdin, resources, and names
kubectl delete -f config-file.yaml # Get logs from a pod
kubectl logs pod-name # Execute a command in a container
kubectl exec -it pod-name -- /bin/bash # Forward a port from a pod to the local machine
kubectl port-forward pod-name 8080:80

# Add a Helm repository
helm repo add repo-name https://example.com/repo # Update all Helm repositories
helm repo update # Search for charts in a Helm repository
helm search repo repo-name # Install a Helm chart
helm install release-name repo-name/chart-name # List all Helm releases across all namespaces
helm list --all-namespaces # Uninstall a Helm release
helm uninstall release-name # Upgrade an existing Helm release
helm upgrade release-name repo-name/chart-name # Get the status of a Helm release
helm status release-name # Show the history of a Helm release
helm history release-name

# Run an Ansible playbook
ansible-playbook playbook.yml -i inventory.ini # Run a single Ansible ad-hoc command
ansible all -m ping # List all available Ansible roles
ansible-galaxy list # Install a role from Ansible Galaxy
ansible-galaxy install role-name # Test an Ansible inventory file
ansible-inventory --list -i inventory.ini # Run an Ansible playbook with increased verbosity
ansible-playbook playbook.yml -vvv

# Initialize a Terraform configuration directory
terraform init # Plan the changes required by the Terraform configuration
terraform plan # Apply the changes required by the Terraform configuration
terraform apply # Create a Terraform execution plan and save it to a file (recommended)
terraform plan -out="tfplan.out" # Apply the changes from saved plan
terraform apply "tfplan.out" # Apply the changes automatically (use with your own risk, suitable for automation tasks)
terraform apply --auto-aprove # Destroy all the resources managed by Terraform
terraform destroy # Validate the Terraform configuration files
terraform validate # Format Terraform configuration files
terraform fmt # Show the current state of Terraform-managed infrastructure
terraform show # Refresh the state file with the real infrastructure
terraform refresh # List the available Terraform providers
terraform providers

# Connect to a PostgreSQL database
psql -h hostname -U username -d database_name # List all databases
psql -c "\l" # List all tables in the current database
psql -c "\dt" # Show the structure of a specific table
psql -c "\d table_name" # Create a new database
createdb new_database_name # Drop an existing database
dropdb database_name # Create a new user
createuser new_user_name # Drop an existing user
dropuser user_name # Grant all privileges on a database to a user
psql -c "GRANT ALL PRIVILEGES ON DATABASE database_name TO user_name" # Revoke all privileges on a database from a user
psql -c "REVOKE ALL PRIVILEGES ON DATABASE database_name FROM user_name" # Backup a PostgreSQL database to a file
pg_dump database_name > backup_file.sql # Restore a PostgreSQL database from a backup file
psql database_name < backup_file.sql

# Run a python script
python python_script.py # Install a package using pip
pip install package-name # Install a specific version of a package
pip install package-name==1.2.3 # Uninstall a package
pip uninstall package-name # List all installed packages
pip list # Freeze installed packages into a requirements file
pip freeze > requirements.txt # Install packages from a requirements file
pip install -r requirements.txt

# Login to Azure
az login # Login with device code
az login --use-device-code # Get the details of a subscription
az account show # List all subscriptions associated with your account
az account list --output table # Set a specific subscription as default
az account set --subscription "SUBSCRIPTION_ID" # List all resource groups
az group list --output table