src/UnixEnvironment.php
private function isValidFullPath(string $path): bool
    {
        $valid = false;
        if ('/' === substr($path, 0, 1) && is_executable($path)) {
            $valid = true;
        }

        return $valid;
    }
private function isValidFullPath(string $path): bool
    {
        $valid = false;
        if ('/' === substr($path, 0, 1) && is_executable($path)) {
            $valid = true;
        }

        return $valid;
    }
Returns true if the path points to an executable file.