R1> enable
R1# config t
R1(config)#hostname ?
  WORD  This system's network name
R1(config)# hostname california
california(config)# int fa0/0
california(config-if)# ip address 1.2.3.4 255.255.255.0
california(config-if)# description ?
  LINE  Description that will be truncated to 240 characters.

california(config-if)# description ok
california(config-if)# duplex ?
  auto  Enable AUTO duplex configuration
  full  Force full duplex operation
  half  Force half-duplex operation

california(config-if)# duplex half
california(config-if)# int fa0/1
california(config-if)# ip address 2.3.4.5 ?
  A.B.C.D  IP subnet mask

california(config-if)# ip address 2.3.4.5 255.255.255.0
california(config-if)# desc manchester
california(config-if)# duplex full
california(config-if)# no shutdown
california(config-if)# exit