Creating a Private Ethereum Blockchain

These are basic instructions for creating a private Ethereum blockchain using Geth on Mac OSX.  Geth is a multipurpose command line tool that runs a full Ethereum node. Geth offers multiple interfaces: the command line subcommands and options, a JSON-RPC server and an interactive console. The Geth console is a JavaScript environment that contains all of the main features that you probably want.

Open the Mac OSX Terminal console and:

First: Install Homebrew and make sure it is up to date:

brew update

brew upgrade

Second: Use these commands to install Ethereum:

brew tap ethereum/ethereum

brew install ethereum

Third: Create a private blockchain:

geth genesis

*Note: At this point the Mac OSX Terminal console will show many real-time log entries.  This real-time display of log entries makes it impossible to use the console to enter any additional commands.  You will need to open a Geth console.

Fourth: Open a Geth console that won’t display all log entries on screen:

Open a second Mac OSX Terminal console and type:

geth attach

Fifth: Create a personal account:

From the newly opened Geth console type:


Enter a memorable password.