Using CLI For First Time

I'd like to use CodeIgniter's CLI. When I do this:
> php spark list
I get:
PHP Fatal error:  Uncaught Error: Undefined constant "CodeIgniter\CLI\ENVIRONMENT" in /var/www/html/vendor/codeigniter4/framework/system/CLI/CLI.php:666
Stack trace:
#0 /var/www/html/vendor/codeigniter4/framework/system/CLI/CLI.php(707): CodeIgniter\CLI\CLI:treamSupports()
#1 /var/www/html/vendor/codeigniter4/framework/system/CLI/CLI.php(159): CodeIgniter\CLI\CLI::hasColorSupport()
#2 /var/www/html/vendor/codeigniter4/framework/system/CLI/CLI.php(1115): CodeIgniter\CLI\CLI::init()
#3 /var/www/html/vendor/codeigniter4/framework/system/Autoloader/Autoloader.php(312): include_once('...')
#4 /var/www/html/vendor/codeigniter4/framework/system/Autoloader/Autoloader.php(289): CodeIgniter\Autoloader\Autoloader->includeFile()
#5 /var/www/html/vendor/codeigniter4/framework/system/Autoloader/Autoloader.php(267): CodeIgniter\Autoloader\Autoloader->loadInNamespace()
#6 /var/www/html/vendor/codeigniter4/framework/system/CLI/Console.php(49): CodeIgniter\Autoloader\Autoloader->loadClass()
#7 /var/www/html/spark(60): CodeIgniter\CLI\Console->showHeader()
#8 {main}
  thrown in /var/www/html/vendor/codeigniter4/framework/system/CLI/CLI.php on line 666

What is not setup properly?

---

Never mind. I had removed the spark script from my docroot because up to now I've never needed to use the CLI.

Simpler is always better