Ubuntu 18.04: Install MATE for desktop environment

The following command will install MATE.

$ sudo apt install -y ubuntu-mate-desktop
<snip>
check for a default display manager.

  1. gdm3  2. lightdm

Default display manager: lightdm
<snip>
$ sudo reboot

The following makes selecting display manager be automated.

$ sudo apt install -y expect
$ cat <<EOF | expect
set timeout -1
spawn sudo apt install -y ubuntu-mate-desktop
expect "Default display manager: "
send "lightdm\n"
expect eof
EOF
$ sudo reboo

After reboot, lightdm-gtk-greeter will be started. You can select other desktop environment.

MATE is displayed.

The following command will uninstall MATE.

$ sudo apt remove -y ubuntu-mate-desktop mate-* ubuntu-mate-* \
       plymouth-theme-ubuntu-mate-* lightdm
$ sudo apt autoremove -y
$ sudo apt install --reinstall -y gdm3
$ sudo reboot