When trying to run php cron through the CLI, an error occurs: the input file could not be opened.
php /var/www/cron/example.php
Could not open input file: /var/www/cron/example.php
The reason for the error is that the file does not exist at the specified path, double-check the existence of the file, for example:
cat /var/www/cron/example.php
If the file exists, the contents of the file will be printed in the terminal, otherwise there will be an error: cat: /var/www/example.php : No such file or directory