change ip, gateway, dns through command line

DNS:

vi /etc/resolve.conf

IP & netmask:

ifconfig eth0 xxx.xxx.xxx.xxx netmask xxx.xxx.xxx.xxx

Gateway?(need to rethink)

add a "network to be gatewayed" by a certain device say eth1.
route add mygateway eth1
route add -net 192.168.32.0 netmask 255.255.255.0 gw mygateway