Easily create a sudoer, SSH-keyed new user on a linux machine

user_create.sh

#!/bin/bash -e
#
# Creates user and adds public key
# Must be run as root
#
# Requires:
#  1) Full name
#  2) Username
#  3) Public key


if (( "$#" != 3 ))
then
  echo "Creates a user with sudo rights and loads their public key."
  echo "Usage: $(basename $0) FULL_NAME USERNAME PUBLIC_KEY"
  exit 1
fi

fullname=$1
username=$2
key=$3

useradd -c "$fullname" $username
mkdir -m 700 /home/$username/.ssh
echo "$key" > /home/$username/.ssh/authorized_keys
chmod 600 /home/$username/.ssh/authorized_keys
chown -R $username:$username /home/$username/.ssh
echo -e "$username\t\tALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers

echo 'User created'