To see what VPN connections you have available or the status of your connections on the mac, you would type:
scutil --nc list
To start a VPN connection, you would type:
scutil --nc start "name of vpn connection"
To stop it, you would type:
scutil --nc stop "name of vpn connection"
Again, to get status at any time, type:
scutil --nc list
These commands do not launch the GUI, so outside of using the "scutil --nc list" command, you will not receive any status of it being connected.
I hope that helps.