Assign new ip =   ifconfig eth0 192.168.1.10

Assign IP/Subnet =  ifconfig eth0 192.168.1.10 netmask 255.255.255.0

Assign Default Gateway=  route add default gw 192.168.1.1

Assign multiple IP’s =  ifconfig eth0:0 192.168.1.10 netmask 255.255.255.0

Assign second IP =  ifconfig eth0:1 10.1.10.20 netmask 255.255.0.0

Buy me a beer