IP Routing table management subcommand. More information: https://manned.org/ip-route.
ip route {{show|list}}
sudo ip route add default via {{gateway_ip}}
eth0
:sudo ip route add default dev {{eth0}}
sudo ip route add {{destination_ip}} via {{gateway_ip}} dev {{eth0}}
sudo ip route del {{destination_ip}} dev {{eth0}}
sudo ip route {{change|replace}} {{destination_ip}} via {{gateway_ip}} dev {{eth0}}
ip route get {{destination_ip}}