A bookmark of essential command-line commands for a software engineer’s daily tasks 📑
# TIPS: Press `Ctrl + R` to find your previous 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
chmod 0600 /path/to/directory
# Change directory owner
sudo chown -R user:user folder
# 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
ping google.com
nslookup google.com
tracepath google.com
# 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/
# Control file content
echo "first line" > file.txt
echo "second line" >> file.txt
# SCP commands
scp -r username@IP:/path/on/remote /path/on/local
scp -r -i /path/to/key.pem username@IP:/path/on/remote /path/on/local
scp -r -P 12345 -i /path/to/key.pem username@IP:/path/on/remote /path/on/local
# DNS check
dig domain.com
# Generate SSH keys
ssh-keygen -t rsa
# SSH to a server using username/password
ssh user@1.2.3.4
# SSH to a server using key
ssh -i user_key.pem user@1.2.3.4
# Use locally available keys to authorise logins on a remote machine
ssh-copy-id user@1.2.3.4
# 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
# Configure git info, remove '--global' flag if you want to config for project only
git config --global user.name "Your Name"
git config --global user.email "your.email@example.com"
# Verify
git config -l
# Clone repo via HTTPS
git clone https://github.com/REPO_OWNER/repo.git
# Clone with username
git clone https://username@github.com/REPO_OWNER/repo.git
# Clone repo via SSH
git clone git@github.com: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 changes to the staging area
git add .
git add file_name1 file_name2 folder_name1
# 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
# Linux Export KUBECONFIG to access the cluster
export KUBECONFIG=/path/to/kubeconfig.conf
# Window Export KUBECONFIG to access the cluster
$env: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
# Apply with secret var
terraform apply -var-file="secret.tfvars"
# 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
# Get subscription ID
az account show --query id --output tsv
# 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
# List location
az account list-locations