create-user.sh

#!/bin/bash

USER_DISK_PATH=/home/user-disks
USER_DISK_SIZE_IN_BYTES=1099511627776
USER_PASSWORD_LENGTH=24
USER_DEFAULT_SHELL=/bin/bash

if [ "$EUID" -ne 0 ]
  then echo "Please run as root"
  exit 1
fi

read -p "Insert new user's username: " new_user

if [ -z $new_user ]; then
    echo "Please insert an username !"
    exit 1
elif getent passwd $new_user >/dev/null; then
    echo "User already exists !"
    exit 1
fi

if [ ! -d $USER_DISK_PATH ]; then
    echo "Creating folder for user disk at" $USER_DISK_PATH
    mkdir -p $USER_DISK_PATH
fi

USER_DISK_FILE=$USER_DISK_PATH/$new_user.img

echo "Creating user disk image" $USER_DISK_FILE
fallocate -l $USER_DISK_SIZE_IN_BYTES $USER_DISK_FILE
sudo mkfs.ext4 -Enodiscard $USER_DISK_FILE

USER_MOUNT_POINT=/home/$new_user

echo "Create user mountpoint" $USER_MOUNT_POINT
mkdir -p $USER_MOUNT_POINT

echo "Writing entry to fstab"
echo $USER_DISK_FILE $USER_MOUNT_POINT ext4 defaults 0 0 >> /etc/fstab
mount $USER_MOUNT_POINT

#while true ; do
#    read -s -p "Insert a password for user ${new_user}: " new_user_psw
#    if [ ! -z $new_user_psw ]; then
#        break
#    fi
#    echo "Please insert a password !"
#done

echo "Creating user" $new_user
useradd $new_user --no-create-home --home $USER_MOUNT_POINT -s $USER_DEFAULT_SHELL
new_user_psw=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w $USER_PASSWORD_LENGTH | head -n 1)
echo "$new_user:$new_user_psw" | chpasswd

cp -rT /etc/skel $USER_MOUNT_POINT
chown -R $new_user:$new_user $USER_MOUNT_POINT

echo "User" $new_user "create successfully with password" $new_user_psw
echo "Make sure to change it"