Disable root account on Ubuntu (should be default) and Debian

DisableRoot.sh

#!/bin/sh
# Disable root on Ubuntu/Debian
# (c) 2020-2021 Benjamin 'Benno' Falkner

##### NOT TESTET YET #####

set -e # halt on error, (debug add '-x')
cat <<EOF
Disable Root on Debian and Ubuntu
(c) 2020 Benjamin 'Benno' Falkner (MIT-License)
EOF

# Variables
# USER is a system variable should exist


# INSTALL SUDO
# function to install sodo command
install_sudo(){
  echo "Please enter your root password."
  su -c "apt-get install sudo" root || { echo "Please set all ."; exit 1}
}
# we can not expect sudo has been installed
test -n $(which sudo) || install_sudo

# check if user is in sudo group or add user to group (again the root password is needed)
groups | grep -w sudo || su -c "usermod -a -G sudo $USER" root & su - $USER

echo "sudo is now working for current user. Please use current user password form now on."

# disable root 
sudo passwd -d root
sudo passwd -l root