Simple CLI color class

ColorCLI.php

class ColorCLI {
	
	static $foreground_colors = array(
		'black'        => '0;30',
		'dark_gray'    => '1;30',
		'blue'         => '0;34',
		'light_blue'   => '1;34',
		'green'        => '0;32',
		'light_green'  => '1;32',
		'cyan'         => '0;36',
		'light_cyan'   => '1;36',
		'red'          => '0;31',
		'light_red'    => '1;31',
		'purple'       => '0;35',
		'light_purple' => '1;35',
		'brown'        => '0;33',
		'yellow'       => '1;33',
		'light_gray'   => '0;37',
		'white'        => '1;37',
	);
	
	static $background_colors = array(
		'black'        => '40',
		'red'          => '41',
		'green'        => '42',
		'yellow'       => '43',
		'blue'         => '44',
		'magenta'      => '45',
		'cyan'         => '46',
		'light_gray'   => '47',
	);

	// Returns colored string
	static function string($string, $foreground_color = null, $background_color = null) {
		$colored_string = "";

		// Check if given foreground color found
		if( isset(self::$foreground_colors[$foreground_color]) ) {
			$colored_string .= "\033[" . self::$foreground_colors[$foreground_color] . "m";
		}
		// Check if given background color found
		if (isset(self::$background_colors[$background_color])) {
			$colored_string .= "\033[" . self::$background_colors[$background_color] . "m";
		}

		// Add string and end coloring
		$colored_string .=  $string . "\033[0m";

		return $colored_string;
	}
	
}

foreach( $libraries as $library ) {
	
	echo ColorCLI::string($library, 'red') . PHP_EOL;
	$dirs = scandir($library);

	foreach( $dirs as $dir ) {
		if( $dir[0] == '.' || !is_dir( $library . $dir) ) continue;
		echo $dir . PHP_EOL;
		
	}
	
}