Add Unix user with only SSH key (without password)

add-user-with-ssh-key.sh

#!/bin/sh
#
# License: CC0
# Author: Valerio Bozzolan
# https://gist.github.com/valerio-bozzolan/70e0184478fa0ffa52a37745ac04f333
#
# Quickly create an user without password but with an SSH key
#

USERNAME="$1"
KEY="$2"

if [ -z "$KEY" ]; then
echo "Usage: "
echo " $0 'USERNAME' 'SSH-KEY... comment'"
exit 1
fi

adduser "$USERNAME" --disabled-password
mkdir --parents                  /home/"$USERNAME"/.ssh
echo "$KEY"                   >> /home/"$USERNAME"/.ssh/authorized_keys
chown "$USERNAME":"$USERNAME" -R /home/"$USERNAME"/.ssh
chmod 640                        /home/"$USERNAME"/.ssh/authorized_keys
chmod 755                        /home/"$USERNAME"/.ssh