Common Log file locations

SYSTEM LOGS(where you check cron job results, system results):

sudo vim /var/log/syslog

// just to see cron
 grep CRON /var/log/syslog

https://askubuntu.com/questions/56683/where-is-the-cron-crontab-log


Apache 2 log (including errors on fail to start):
 /var/log/apache2/

https://askubuntu.com/questions/119571/where-can-i-find-messages-related-to-apache-start-up


Apache2 restart 

service apache2 restart
service apache2 reload
service apache2 status 

https://stackoverflow.com/questions/16156079/how-to-check-is-apache2-is-stopped-in-ubuntu