I'm trying to make Ethereum private blockchain. But facing a error while running this

"geth --nodiscover --networkid 42 --datadir .ethereum/ --unlock 0x526d8a6baa472da27215f748236af96bc9f256d7--mine --rpc --rpcapi eth,net,web3 --rpcaddr"

While the error I'm getting is

"Incorrect Usage. flag needs an argument: -rpcaddr"