How to install
You need the repository, where
multiverse. When you are adding a repository, you should also add
universe with many useful packages, for example
ubuntu-restricted-extras, which is useful for playing multimedia.
sudo add-apt-repository multiverse
sudo add-apt-repository universe
In earlier versions you should run
sudo apt update
but it is automatically run via
add-apt-repository in 18.04 LTS.
Now you should be able to install with
sudo apt install libdvd-pkg
How to make
libdvd-pkg survive shutdown and reboot.
You can do this in a live-only drive, but it will disappear at shutdown or reboot. If you want it to survive, you should create a persistent live system.
The following links describe how to create a persistent live drive
How to clone a DVD
If you want to create an image file of a DVD disk or clone it to another DVD disk, I suggest that you use a safer tool than
k3b is a good tool for that purpose, and you get it from the repository
sudo apt install k3b