Show Connections
$ nmcli con
Start a Connection
$ nmcli con up id gateway.hollandamerica.com
$ nmcli con up id ConnectName
Stop a Connection
$ nmcli con down id gateway.hollandamerica.com
$ nmcli con down id ConnectionName
Refer: http://askubuntu.com/questions/57339/connect-disconnect-from-vpn-from-the-command-line