Ubuntu toggle between text and graphical boot modes

boot-mode.sh

# From https://askubuntu.com/a/870226
# Tested on Ubuntu 17.04 on 2017-05-15

# To boot Ubuntu Desktop without X one time, add systemd.unit=multi-user.target to the linux command line in GRUB.

# To make this the default, use:
sudo systemctl set-default multi-user.target

# To return to default booting into X, use:
sudo systemctl set-default graphical.target

# To see the current default target:
sudo systemctl get-default