Command Line Password Generator

Overview

A powerful Node.js command-line tool that generates secure random passwords with customizable options. The tool automatically copies generated passwords to your system clipboard for immediate use and optionally saves them to a local file. Perfect for developers, security professionals, and anyone who needs quick access to strong passwords.

Key Features

• Secure Random Generation: Creates cryptographically strong passwords using random character selection
• Customizable Length: Generate passwords from 1 to any desired length (default: 8 characters)
• Character Type Control: Include or exclude numbers and symbols as needed
• Automatic Clipboard Copy: Instantly copies generated passwords to system clipboard
• Optional Persistence: Save passwords to passwords.txt file with -s flag
• Global Installation: Install globally via npm link to use from anywhere
• Colored Output: Beautiful terminal output using Chalk for better readability
• Cross-platform: Works on Windows, macOS, and Linux

How It Works

Character Set Creation

Builds a pool of characters including uppercase and lowercase letters (always included), numbers (optional, included by default), and symbols (optional, included by default).

Random Password Generation

Randomly selects characters from the pool using secure random methods to create a password of the specified length, ensuring each character has equal probability of selection.

Clipboard Integration

Uses Clipboardy for cross-platform clipboard access, automatically copying the generated password for immediate pasting into applications.

Optional File Persistence

When the -s flag is used, appends the generated password with timestamp to passwords.txt in the project root directory.

Tech Stack

• Runtime: Node.js
• CLI Framework: Commander.js
• Terminal Styling: Chalk
• Clipboard: Clipboardy
• Language: JavaScript

Technical Highlights

Commander.js Integration

Utilized Commander.js for robust command-line interface with option parsing, default values, help generation, and version management.

Secure Random Generation

Implemented secure password generation using JavaScript's random methods with proper character pool shuffling for true randomness.

Cross-platform Clipboard

Integrated Clipboardy library for seamless clipboard access across Windows, macOS, and Linux operating systems.

Global npm Command

Configured package.json with proper bin field and used npm link to create globally accessible passgen command.

Terminal Styling

Applied Chalk library for colored terminal output, making success messages green, errors red, and passwords blue for visual clarity.

Usage Examples

# Generate an 8-character password (default)
passgen

# Generate a 16-character password
passgen -l 16

# Generate a password without numbers
passgen --no-numbers

# Generate a password without symbols
passgen --no-symbols

# Generate a 12-character password with only letters and numbers
passgen -l 12 --no-symbols

# Generate a password and save it to passwords.txt
passgen -s

# Combine multiple options
passgen -l 20 -s --no-symbols

Command Options

• -l, --length <number> - Password length (default: 8)
• -s, --save - Save password to passwords.txt
• -nn, --no-numbers - Exclude numbers
• -ns, --no-symbols - Exclude symbols
• -h, --help - Display help information
• -V, --version - Display version number

Installation

Local Usage

npm install
node index.js [options]

Global Installation

npm link
passgen [options]

# Remove global command
npm unlink

Challenges & Solutions

CLI Argument Parsing

Implemented Commander.js framework to handle command-line arguments, options, flags, and generate automatic help documentation with proper error handling.

Cross-platform Clipboard Integration

Used Clipboardy library to handle clipboard operations across different operating systems (Windows, macOS, Linux) with consistent API.

Character Pool Randomization

Built secure character pool system that dynamically includes/excludes numbers and symbols based on user flags, ensuring true random selection.

File System Persistence

Implemented fs.appendFile() to save passwords with timestamps to local file when requested, with proper error handling for file operations.

Global npm Package Installation

Configured package.json with bin field and proper entry point, using npm link to create globally accessible command-line tool.

Project Structure

passgen/
├── index.js                 # Main CLI entry point
├── package.json             # Dependencies and configuration
├── passwords.txt            # Generated when using -s flag
└── utils/
   ├── createPassword.js    # Password generation logic
   └── savePassword.js      # File saving functionality

Problem Solved

Generating strong passwords manually is tedious and often results in weak, predictable patterns. Online password generators require trusting third-party websites with your security. This CLI tool generates secure passwords locally, instantly copies them to clipboard, and works offline - no trust required.

What Makes It Unique

Unlike browser-based tools, this runs entirely on your machine with no network requests. The Commander.js integration provides a professional CLI experience with proper help docs and version info. The npm link feature turns it into a globally accessible command - type passgen from anywhere in your terminal.

Impact

• CLI Development Skills: Mastered Node.js CLI development patterns including Commander.js, Chalk for styling, and Clipboardy for clipboard access
• npm Package Publishing: Learned how to structure packages for global installation using npm link and bin configuration
• Daily Utility: Created a tool I actually use regularly for generating passwords during development and personal use

Future Enhancements

• Add password strength indicator
• Implement password history with encryption
• Add pronounceable password generation
• Create GUI version for non-technical users
• Add password expiry tracking
• Implement secure password vault
• Add password pattern customization
• Create browser extension version