#!/bin/sh
if (( $(id -u) != 0 )); then echo "Please run with sudo" && exit 1; fi
PSID=$( (/usr/sbin/scutil | /usr/bin/grep PrimaryService | /usr/bin/sed -e 's/.*PrimaryService : //')<< EOF
get State:/Network/Global/IPv4
d.show
quit
EOF
)

/usr/sbin/scutil << EOF
remove State:/Network/Service/$PSID/DNS
quit
EOF

echo -e "Please toggle your network adapter on/off to refresh DNS servers from DHCP"