nmcli usage.

import OpenVPN config file from command line with NetworkManager

Type the following apt-get command or apt command to install the Gnome NetworkManager OpenVPN plugin under a Debian or Ubuntu Linux. For example:

sudo apt install network-manager-openvpn-gnome openvpn-systemd-resolved

The syntax is:

sudo nmcli connection import type openvpn file /home/vivek/ubuntu16.04LTS.ovpn

Your connection is called ‘ubuntu16.04LTS’ and to make connection to the OpenVPN server, run:

nmcli connection up ubuntu16.04LTS

To see IPv4/IPv6 OpenVPN client IP and other info, run:

nmcli connection show ubuntu16.04LTS | egrep -i 'IP4|IPV6'
nmcli connection show ubuntu16.04LTS | egrep -i 'IP4'