https://github.com/hwdsl2/setup-ipsec-vpn

wget https://git.io/vpnsetup -O vpnsetup.sh && sudo sh vpnsetup.sh

OR,

wget https://git.io/vpnsetup -O vpnsetup.sh

nano -w vpnsetup.sh

[Replace with your own values: YOUR_IPSEC_PSK, YOUR_USERNAME and YOUR_PASSWORD]

sudo sh vpnsetup.sh