Ubuntu 18.04: Install Xfce for desktop environment

The following command will install Xfce.

$ sudo apt install -y xubuntu-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 xubuntu-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.

Xfce is displayed.

The following command will uninstall Xfce.

$ sudo apt remove -y xubuntu-desktop xfdesktop4 xfce4-* libxfce4-* \
       lightdm
$ sudo apt autoremove -y
$ sudo apt install --reinstall -y gdm3
$ sudo reboot