Advanced CLI Argument Parsing with getopts

#!/bin/bash

# Default values
VERBOSE=false
ENVIRONMENT="development"
CONFIG_FILE="default.conf"

# Function to display help message
display_help() {
    echo "Usage: $0 [OPTIONS]"
    echo "  -v                  Enable verbose output."
    echo "  -e <env>            Specify environment (e.g., 'production', 'staging'). Default: development"
    echo "  -c <file>           Specify configuration file path. Default: default.conf"
    echo "  -h                  Display this help message."
    echo
    echo "Example: $0 -v -e production -c /etc/app/prod.conf"
    exit 0
}

# Parse short options using getopts
while getopts ":ve:c:h" opt; do
    case $opt in
        v) VERBOSE=true ;;
        e) ENVIRONMENT="$OPTARG" ;;
        c) CONFIG_FILE="$OPTARG" ;;
        h) display_help ;;
        \?)
            echo "Invalid option: -$OPTARG" >&2
            display_help
            ;;
        :)
            echo "Option -$OPTARG requires an argument." >&2
            display_help
            ;;
    esac
done
shift $((OPTIND-1)) # Shift positional parameters to exclude options

# Handle remaining arguments (if any)
if [ "$#" -gt 0 ]; then
    echo "Unexpected arguments: $@" >&2
    display_help
fi

# Script logic using parsed options
echo "--- Script Configuration ---"
echo "Verbose: $VERBOSE"
echo "Environment: $ENVIRONMENT"
echo "Config File: $CONFIG_FILE"
echo "----------------------------"

if $VERBOSE; then
    echo "Running in verbose mode..."
fi

echo "Executing main logic for '$ENVIRONMENT' using '$CONFIG_FILE'..."

# Add your main script logic here
# e.g., deploy to a specific environment, run tests with a config