arch-automated-installer/scripts/system-setup/sudo-setup.sh

#!/bin/bash

if [[ $1 == "Debian" ]]; then

    if [[ ! -z $(grep $2 /etc/passwd) ]]; then
        echo "usermod -aG sudo $2"
    else
        echo "Username is Invalid"
        exit 1
    fi

fi

if [[ $1 == "Arch" ]]; then

    if [[ ! -z $(grep $2 /etc/passwd) ]]; then
        echo "usermod -aG wheel $2"
        break
    else
        echo "Username is Invalid"
        exit 1
    fi

fi