BASH

Robust Command Line Argument Parsing

Master parsing command-line options and arguments in bash scripts using `getopts` for creating flexible and user-friendly utilities with short flags.

#!/bin/bash

# Default values
VERBOSE=0
OUTPUT_FILE=""
INPUT_PATH=""

usage() {
    echo "Usage: $0 [-v] [-o <output_file>] <input_path>"
    echo "  -v: Verbose mode"
    echo "  -o <output_file>: Specify an output file"
    echo "  <input_path>: Required input file or directory path"
    exit 1
}

# Parse options
while getopts "vo:" opt; do
    case $opt in
        v) VERBOSE=1 ;;
        o) OUTPUT_FILE="$OPTARG" ;;
        \?) usage ;; # Handle invalid options
    esac
done

# Shift parsed options so that remaining arguments are positional
shift $((OPTIND - 1))

# Check for required positional argument
if [ -z "$1" ]; then
    echo "Error: Input path is required."
    usage
fi
INPUT_PATH="$1"

# --- Script Logic Starts Here ---
echo "Processing input path: $INPUT_PATH"

if [ -n "$OUTPUT_FILE" ]; then
    echo "Output will be redirected to: $OUTPUT_FILE"
    # Example: command > "$OUTPUT_FILE"
fi

if [ "$VERBOSE" -eq 1 ]; then
    echo "Verbose mode is enabled."
    echo "Additional debug information here..."
fi

# Example: Perform some operation with INPUT_PATH
# ls -l "$INPUT_PATH"

How it works: This script demonstrates robust command-line argument parsing using `getopts`. It allows for defining short options like `-v` for verbose mode and `-o <output_file>` to specify an output file. A `usage` function provides help, and `shift $((OPTIND - 1))` cleanly separates options from positional arguments. The script checks for a required positional argument (`INPUT_PATH`) and then uses the parsed values in its main logic, making scripts more versatile.

Robust Command Line Argument Parsing

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