Usage ***** In order to interact with a Tezos node, you may use RPC calls through the client using this command ``tezos-client rpc call ``. For instance, if you wish to request the current balance of a given block and contract, you can call the associated RPC via the command : ``$ tezos-client rpc call /blocks//proto/context/contracts//balance``. A RPC may takes an *input* and generates an *output* both in JSON format. For example, the previous RPC call, that does not require an input, would display on the standard output : ``{ "balance": "4000000000000" }``. When calling a RPC that requires an input through command-line, you will be prompted to provide the JSON input in your default configured text editor. In the following sections, you may find the complete list of RPCs available for the client and for the protocol Alpha. You may also find input, output and errors JSON schema.