docs: function concatFiles() {
  	return Promise.all(argv._.map(handleGlob)).then(globs => {
  		const files = globs.reduce((acc, cur) => acc.concat(cur), []);
  
  		if (
  			(files.length < 2 && typeof argv.banner === 'undefined' && !argv.footer) ||
  			(files.length === 0 && (typeof argv.banner === 'undefined' || !argv.footer))
  		) {
  			throw new Error(
  				chalk.bold.red('Require at least 2 file, banner or footer to concatenate. ("ncat --help" for help)\n')
  			);
  		}
  		return files.forEach(file => {
  			concat.add(file.file, file.content, file.map);
  		});
  	});
  }