Turn off monitor automaticlly in Linux CLI

Add consoleblank to the GRUB commandline:

sudo nano /etc/default/grub

Once there, just add consoleblank=60 to GRUB_CMDLINE_DEFAULT, it should look like this:

GRUB_CMDLINE_LINUX_DEFAULT="quiet consoleblank=60"

Then close the file and save it, after that just run sudo update-grub and voila, every time you boot the screen will turn off automatically every 60 sec. (again, if idle).