Since I've been manually updating Ubuntu MATE 16.04 using apt update, upgrade I also manually reboot using this command sudo init 6
Once I forgot sudo and it worked; further testing proved that reboot and shutdown also functioned without using sudo.
I tested this using vanilla Ubuntu 14.04 and found that sudo was mandatory.
reboot
andshutdown -h now
(which are easier to remember, in my opinion)? Also, I can second your observation thatsudo
is mandatory with bothreboot
,shutdown -h now
andinit 6
on a near-vanilla 14.04. It's not possible by default to use the aforementioned commands withoutsudo
.