Toggle a given VPN, eventually ask for password

toggle-vpn.sh

#!/usr/bin/env bash

# usage: toggle-vpn.sh vpn-name

set -e           # this script exits on error
set -o pipefail  # a pipeline returns error code if any command fails
set -u           # unset variables as an error, and immediately exit

command -v nmcli > /dev/null  # ensure nmcli is installed

VPN=$1

# ensure we do not try to shutdown ethernet or wifi
nmcli con | grep vpn | cut -d' ' -f1 | grep "^${VPN}$" > /dev/null

# try to shutdown, otherwise try to connect without passwd, otherwise ask for it
nmcli con down $VPN || nmcli con up $VPN || nmcli --ask con up $VPN ;