Script to configure DNS entries for all network adapters on macOS

mac-dns-get.sh

#!/bin/bash -e

while IFS= read -r adapter_name; do
    echo "DNS Servers configured on $adapter_name:"
    eval "networksetup -getdnsservers \"$adapter_name\""
    echo ""

    echo "Search domain configured on $adapter_name..."
    eval "networksetup -getsearchdomains \"$adapter_name\""
    echo ""
    echo ""
done < <(networksetup -listallhardwareports | grep -i 'hardware port:' | egrep -i -v 'thunderbolt|bridge' | cut -c 16-)

mac-dns-set.sh

#!/bin/bash -e

dns_servers=${1:-'8.8.8.8 8.8.4.4'}
search_domain=${2:-''}

echo "DNS Servers to be used: $dns_servers"
echo "Search domain to be used: $search_domain"
echo ""

while IFS= read -r adapter_name; do
    echo "Setting DNS for $adapter_name..."
    eval "networksetup -setdnsservers \"$adapter_name\" $dns_servers"
    if [[ ! -z "$search_domain" ]]; then
        echo "Setting search domain for $adapter_name..."
        eval "networksetup -setsearchdomains \"$adapter_name\" $search_domain"
    fi
    echo ""
    # The oneliner below gets all possible network hardware ports and removes the
    # "generic" thunderbolt as well as the bridge ones, to make sure we only configure
    # the DNS on actual networking devices (includes any Thunderbolt/USB-C network adapter)
done < <(networksetup -listallhardwareports | grep -i 'hardware port:' | egrep -i -v 'thunderbolt|bridge' | cut -c 16-)

echo "Flushing DNS cache and killind DNS service..."
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

echo "Done!"