Parse Command Line Arguments with getopts for Script Customization

#!/bin/bash

# Default values
VERBOSE=0
ACTION="default"
FILENAME="output.txt"

print_usage() {
  echo "Usage: $0 [-v] [-a <action>] [-f <filename>]
"
  echo "  -v: Enable verbose mode."
  echo "  -a: Specify an action (e.g., 'deploy', 'build'). Default: '$ACTION'."
  echo "  -f: Specify output filename. Default: '$FILENAME'.
"
  exit 1
}

# Parse options using getopts
while getopts "va:f:h" opt; do
  case $opt in
    v)
      VERBOSE=1
      ;;
    a)
      ACTION="$OPTARG"
      ;;
    f)
      FILENAME="$OPTARG"
      ;;
    h)
      print_usage
      ;;
    ?)
      print_usage
      ;;
  esac
done

# Shift off the options and their arguments, so remaining arguments are accessible
shift "$(($OPTIND - 1))"

echo "Script configuration:"
echo "Verbose mode: $VERBOSE"
echo "Action: $ACTION"
echo "Output filename: $FILENAME
"

# Example usage of parsed variables
if [ "$ACTION" == "deploy" ]; then
  if [ "$VERBOSE" -eq 1 ]; then
    echo "Executing deployment in verbose mode..."
  fi
  echo "Deploying to production..."
  # Add deployment logic here
elif [ "$ACTION" == "build" ]; then
  echo "Building project..."
  # Add build logic here
else
  echo "Performing default action."
fi

echo "Script finished."