Display default gateway.
Display basic information.
$ ip -brief address
lo UNKNOWN 127.0.0.1/8 enp3s0 UP 192.168.8.168/24 wlp4s0 DOWN
Display default route.
$ ip route show default
default via 192.168.8.1 dev enp3s0 proto dhcp metric 100
Display default route using JSON.
$ ip -json route show default
[{"dst":"default","gateway":"192.168.8.1","dev":"enp3s0","protocol":"dhcp","metric":100,"flags":[]}]
Display default gateway.
$ ip -json route show default | jq --raw-output '.[].gateway'
192.168.8.1
