Artisan returns blank

Question 1

This problem is pretty common and is usually related to some errors that are not seen in the CLI like custom classes that failed to load, are you sure you have error reporting on?

Edit the file artisan and add the following lines just after the PHP opening tag <?php:

ini_set('display_errors',1);
error_reporting(-1);

Try running artisan again and see if there is any output.

If that doesn't work try reverting app/start/global.php to it's default state.

Question 2

Running composer install solved the problem.

Question 3

The solution for me was like @TheodoreR.Smith mentioned, there was an exit in a controller's __construct(). I removed it and route:list worked fine.

Question 4

Came here after a cronjob wouldn't execute because of artisan containing an error in the CLI, thanks to this answer. So dropping my answer in case it could help someone.

The solution is switching to PHP 7.1+ (7.2 in my case) due to Laravel requirements.

Switching to 7.2 for me, wasn't enough. Both Apache and CLI were switched to 7.2 but the cronjob uses the default PHP version of the server (cPanel managed). Specifically executing the 7.2 version (in stead of global PHP) solved it for me, the cronjob command is:

 * * * * * /usr/local/bin/ea-php72 /path/to/laravel/artisan schedule:run >/dev/null 2>&1

(remove > /dev/null 2>&1 if you want to see the output and bugfix the commands)

Question 5

Make sure you don't have any exit() or die() in your route file.

That was the issue in my case as I was in the middle of testing some code in the route file when I realized that I couldn't run any artisan command.