system/CLI/CLI.php
public static function error(string $text, string $foreground = 'light_red', string $background = null)
	{
		if ($foreground || $background)
		{
			$text = static::color($text, $foreground, $background);
		}

		fwrite(STDERR, $text . PHP_EOL);
	}
public static function error(string $text, string $foreground = 'light_red', string $background = null)
	{
		if ($foreground || $background)
		{
			$text = static::color($text, $foreground, $background);
		}

		fwrite(STDERR, $text . PHP_EOL);
	}
Outputs an error to the CLI using STDERR instead of STDOUT

@param string|array $text       The text to output, or array of errors
@param string       $foreground
@param string       $background