我已经遇到了这种情况并找到了解决方案.这是因为bitnami中的未知原因，因此cron无法识别php命令.我使用此命令使其正常工作:

I've experienced this and found a solution. It's because of unknown reason in bitnami, so that php command not recognized by cron. I used this command to make it working :

* * * * * /path/to/php/bin/php /home/bitnami/htdocs/project/app/artisan schedule:run 1>> /dev/null 2>&1