index.js

'use strict';
const shebangRegex = require('shebang-regex');

module.exports = (string = '') => {
	const match = string.match(shebangRegex);

	if (!match) {
		return null;
	}

	const [path, argument] = match[0].replace(/#! ?/, '').split(' ');
	const binary = path.split('/').pop();

	if (binary === 'env') {
		return argument;
	}

	return argument ? `${binary} ${argument}` : binary;
};