Ethereum

Ethereum is a crypto platform for running smart contracts and exchanging Ether.

My address is 0xd2f887eda1b28c8714dbb2cf63a59f77fb68fb94

Clients

There are a few clients that you can use.

Go-Ethereum (geth)

The Ethereum client written in Go.

Setup

To compile geth, ensure that you have go, gcc, and make installed. Then run:

$ git clone https://github.com/ethereum/go-ethereum
$ cd go-ethereum
$ make geth

geth will be compiled in build/bin/geth.

Usage

When starting geth, it will automatically start downloading the blockchain. It depends on UDP/30303. Ideally, the client should be accessible publicly via that port.

The default cache size used by geth is quite small, so for an initial sync run:

$ geth --datadir /path/to/ethereum-data --cache=1024

Whilst it is syncing, you can check the state of the client by starting and attaching an interactive console:

$ geth attach
> net.listening
true
> admin.peers
> eth.syncing

To create a private net, provide a custom --networkid value or provide a genesis json file with --genesis.

Other things you may want to do are:

Task	Command
Create an account. Similar to creating a new address.	> personal.newAccount("Write here a good, randomly generated, passphrase!")
Show account balance	> web3.fromWei(eth.getBalance(eth.coinbase), "ether")
Show account address	> eth.coinbase ## or > eth.accounts[0]
Start CPU mining. Useful on testnets	> miner.setEtherbase(eth.accounts[0]) > miner.start()

Other

Backing up your key

Copy the ~/.ethereum/keystore as a backup. It contains your encrypted key. Also, don't forget your passphrase.

Private Test Net

To start your own test network with your own ether, install geth and then do the following:

$ mkdir /tmp/eth/70
$ geth console

## In geth console:
$ personal.newAccount('password')
$ eth.accounts[0]
## you can check the eth.accounts[0] address, copy it and memo to somewhere
## control + c then escape from geth console.


## next make the private net genesisblock json file.
vim privatenet_genesis_block.json 

## this is my sample of testnet genesis block json
{
    "nonce": "0xlitebeefdeadbeef",
    "timestamp": "0x0", 
    "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000", 
    "extraData": "0x634f727365", 
    "gasLimit": "0x8000000", 
    "difficulty": "0x400", 
    "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000", 
    "coinbase": "0x3333333333333333333333333333333333333333",
    "alloc": {
   }
}

## then use the previous eth.accounts[0] value as the etherbase value.
## The datadir should be somewhere else.
geth --datadir="/tmp/eth/70" --etherbase="{should be input }" --genesis privatenet_genesis_block.json console
privatenet

Example:

$ ./geth  --networkid 34093 --genesis ~/ethereum/genesis.json --datadir ~/ethereum --etherbase="0xdc9b165c433c8a6ae48713e8eae926767af0bca0" console
$ miner.start(1)

Then attach to the instance with:

$ ./geth  --networkid 34093 --genesis ~/ethereum/genesis.json --datadir ~/ethereum --etherbase="0xdc9b165c433c8a6ae48713e8eae926767af0bca0" --ipcpath ~/ethereum/geth.ipc attach

Dapp Information

TBA

See Also

Greeter contract tutorial

• https://www.ethereum.org/greeter

Contract Guide

• https://eng.erisindustries.com/tutorials/2015/03/11/solidity-1/

DApp Tutorial

• https://dappsforbeginners.wordpress.com/tutorials/your-first-dapp/

• Chicken Lottery: https://www.reddit.com/r/ethereum/comments/3ivfyn/lotto_pollo_lottery_chicken/