VM bootstraping script to replace login account of AWS Ubuntu instance

replace-default-id

#!/bin/bash

# Default login ID of VM Instance.
# https://docs.aws.amazon.com/ko_kr/AWSEC2/latest/UserGuide/managing-users.html
OLD_ID=ubuntu

# Name a new ID at your taste
NEW_ID=joshua
NEW_HOME=/home/$NEW_ID
AUTH_KEY=$USER_HOME/.ssh/authorized_keys

useradd -m -d $NEW_HOME -s /bin/bash $NEW_ID
usermod -aG adm,dialout,cdrom,floppy,sudo,audio,dip,video,plugdev,netdev,lxd $NEW_ID
sudo -u $ID mkdir $NEW_HOME/.ssh
sudo -u $ID chmod 750 $NEW_HOME/.ssh
cp /home/$OLD_ID/.ssh/authorized_keys $AUTH_KEY
chown $NEW_ID:$NEW_ID $AUTH_KEY
chmod 600 $AUTH_KEY

# /etc/sudoers.d/90-cloud-init-users exists in Ubuntu 20.04
# Check this on the other distros.
sed -i "s/$OLD_ID ALL=(ALL) NOPASSWD:ALL/$NEW_ID ALL=(ALL) NOPASSWD:ALL/g" /etc/sudoers.d/90-cloud-init-users