EOSIO comes with a number of programs. The primary ones that you will use, and the ones that are covered here, are:
nodeos(node + eos = nodeos) - the core EOSIO node daemon that can be configured with plugins to run a node. Example uses are block production, dedicated API endpoints, and local development.
cleos(cli + eos = cleos) - command line interface to interact with the blockchain and to manage wallets.
keosd(key + eos = keosd) - component that securely stores EOSIO keys in wallets.
The basic relationship between these components is illustrated in the following diagram. In the sections that follow, you will build the EOSIO components, and deploy them in a single host, single node test network (testnet) configuration.