I recently setup my first cron activity to run daily. But I started getting output of the execution. This although at the beginning reassured me that everything fine has become an annoyance recently since I know its working well. So this is what I did to stop cron email notifications.
sudo nano -w /etc/cron.daily/dailyjob
Add "> /dev/null 2>&1" at the end of the command. This redirects the output to /dev/null, which means we do not care to see the output.
command > /dev/null 2>&1
Save and exit. Thats it. This should those annoying (at least to me) daily output emails.