In this tutorial, we’re diving deep into the world of documentation. You’ve put all this effort into building a great CLI tool—don’t let it go unnoticed or underused because nobody knows how to make it work! Writing clear, simple, and beginner-friendly documentation is the key to making sure your tool is accessible and widely adopted. Whether you’re building this for yourself, a team, or the open-source community, documentation is what will separate a useful tool from a neglected one.

Why Documentation Matters

Let’s start with a question: Have you ever found an awesome tool but couldn’t figure out how to use it because the documentation was either non-existent or downright confusing? If you’ve been there (and most developers have), you already know how important good documentation is.

Think of documentation as your tool’s first interaction with the world. No matter how great your tool is, if nobody knows how to use it, it’s like building a spaceship and hiding the instructions. Nobody’s going to Mars with it! That’s why docs, especially for open-source projects, are non-negotiable. They’re the bridge between you, the developer, and the people who will benefit from using your tool.

You want your tool to be as easy to use as possible. Your future users (who might be developers just like you) will thank you for taking the time to make things clear and straightforward. Plus, good documentation helps you maintain the project in the long run. When users have clear instructions, they won’t bombard you with questions about how to get things working. A win-win, right?

Writing a Clear README

The README is the backbone of your project’s documentation. It’s the first thing people see when they land on your project’s GitHub page, and it should answer the fundamental questions:

• What does this tool do?
• How do I install it?
• How do I use it?

Let’s break down how to write a great README for your CLI tool. Imagine you’re explaining your project to a friend who’s a developer but hasn’t seen it before.

Step 1: Start with a Concise Description

The very first thing in your README should be a one-liner that clearly explains what your tool does. No fluff, no filler. Just straight to the point.

For our Markdown-to-HTML converter, you might write something like this:

# Markdown to HTML CLI

A simple command-line tool that converts Markdown files to HTML. Easily transform your `.md` files into web-ready HTML in seconds.

This opening line does two things: it explains what the tool is (a Markdown-to-HTML converter), and how it works (through the command line). Anyone reading it should immediately understand what your tool does.

Step 2: Installation Instructions

Next, you’ll want to include a section on how to install the tool. If users can’t figure out how to get it running, they’re not going to stick around to try. Here’s an example of clear installation instructions:

## Installation

To install this CLI tool globally, run the following command:

`npm install -g md2html`

Make sure you specify that the tool should be installed globally using the -g flag, so users can access it from anywhere on their system.

Step 3: Basic Usage

Now comes the really important part: showing users how to use the tool. Provide a simple example, so they can get started immediately.

## Usage

To convert a Markdown file (`input.md`) to HTML, use the following command:

`md2html input.md --output output.html`

This will take `input.md` and generate `output.html` in the current directory.

This example shows the most basic usage of your tool, which is exactly what people want to know right away. You don’t need to overwhelm users with all the possible options—just give them the easiest path to success.

Step 4: Advanced Options

Once you’ve covered the basics, add a section for more advanced options. This is where you can explain different command-line flags, config files, or anything else users might want to customize.

## Options

- `-o, --output <file>`: Specify the output HTML file.
- `-h, --help`: Show help information.

## Example

`md2html input.md --output custom.html`

This command will output the converted file to `custom.html`.

Step 5: Including Contribution Guidelines (Optional)

If your tool is open source, you’ll want to include a Contributing section. This is optional but highly encouraged. It gives developers a clear idea of how they can contribute to the project, report bugs, or suggest improvements.

## Contributing

Contributions are welcome! Please feel free to submit issues or pull requests. If you'd like to help, check out the open issues and see how you can get involved.

Adding Usage Examples

Documentation without examples is like a recipe without pictures. Sure, it might work, but it’s way easier to understand with real-world examples.

People learn faster when they can see how things work, especially when it comes to command-line tools. So, let’s make sure we add a bunch of examples to our README that cover both basic and advanced use cases.

Step 1: Basic Example

We already have this example from the previous section, but it’s worth repeating here for emphasis:

## Basic Example

To convert `input.md` to `output.html`, run the following command:

`md2html input.md --output output.html`

This shows the simplest use case and gives users a clear path to success.

Step 2: Advanced Example

Now let’s show an advanced example that demonstrates a bit more functionality. Maybe the user wants to process multiple files at once, or perhaps they’re using a custom config file.

## Advanced Example

Convert all Markdown files in the `docs` folder to HTML and save the outputs in the `dist` folder:

`md2html docs/*.md --output dist/`

Or, use a configuration file to specify default options:

`md2html input.md --config myconfig.json`

These advanced examples will help your users understand that your tool isn’t limited to simple tasks—it can be customized to fit their workflow. Plus, seeing these examples gives them ideas about how to use the tool in more creative ways.

Creating a Help Command

You’ve written a great README with clear instructions and examples, but sometimes users will want a quick refresher without diving back into the full documentation. That’s where the help command comes in.

Having a built-in help command is a common and highly appreciated feature in CLI tools. With the help flag (--help), users can see a summary of the tool’s capabilities right from the terminal.

Step 1: Adding the Help Command with Commander.js

If you followed the previous tutorial, we’re already using commander.js to handle command-line arguments. One of the nice things about commander is that it automatically generates help messages based on the options you define.

Here’s how to make sure your help command is working:

#!/usr/bin/env node

const { program } = require('commander');

// Set up the CLI commands and options
program
  .version('1.0.0')
  .description('Markdown to HTML converter CLI tool')
  .option('-o, --output <file>', 'Specify the output file')
  .on('--help', function () {
    console.log('');
    console.log('Example:');
    console.log('  $ md2html input.md --output result.html');
  })
  .parse(process.argv);

Step 2: Testing the Help Command

You can test the help command by running:

md2html --help

The output will look something like this:

Usage: md2html [options] <file>

Markdown to HTML converter CLI tool

Options:
  -o, --output <file>  Specify the output file
  -V, --version        Output the version number
  -h, --help           Display help for the command

Example:
  $ md2html input.md --output result.html

This help command gives users a quick and easy way to understand how to use your tool without having to look at the README every time.

Takeaway

At this point, you’ve made your tool far more accessible and user-friendly. With a well-written README, real-world usage examples, and a built-in help command, you’re showing the world that you care about their experience with your project.

Good documentation is like the packaging on a product. It’s the first thing people see, and it can make or break their impression of the tool. But beyond that, it’s also about helping your users get the most out of what you’ve built. And with what you’ve just learned, you’re ensuring that your tool will be easy to pick up and use, even for someone who’s never heard of it before.

In the next tutorial, we’ll go even further by looking at how to test your tool and ensure it works consistently across different environments. We’ll also cover how to publish it to npm so others can start using it right away.