Update for UbuntuMATE 16.04.6 broke the GUI

[Ralf Mardorf]

On Sun, 25 Aug 2019 22:03:38 +0800, Bret Busby wrote:
>I have only one user set up, on each of my systems, from installation;
>me.
>
>On both of the two broken systems; 16.04.6 and 18.04.3,
>sudo adduser
>returns
>
>"
>adduser: Only one or two names allowed.
>"
>
>then, it returns to the prompt.
>
>Both (and, all of my Ubuntu) systems are UbuntuMATE.

'adduser' seems to be interactive on FreeBSD, but seemingly just was
interactive, but obviously isn't anymore on Ubuntu.

Usually on Linux 'sudo useradd -m testusername' creates a user and adds
defaults, IOW home, login shell etc., this might not work on Ubuntu.

You should run 'sudo adduser testusername', this at least should create
a home, but might not add the user to a set of default groups.

The command 'groups' as well as 'id' informs you about the groups that
were or were not automatically added.