如何安装

sudo apt-get update

sudo apt-get install software-properties-common

sudo add-apt-repository -y ppa:ethereum/ethereum

sudo add-apt-repository -y ppa:ethereum/ethereum-dev

sudo apt-get update

sudo apt-get install ethereum

查看安装好的geth版本号

wangzhen@wangzhen-VirtualBox:/opt$ geth version

Geth
Version: 1.8.4-stable
Git Commit: 2423ae01e0d2f853512eb2b46954b5ad0754a897
Architecture: amd64
Protocol Versions: [63 62]
Network Id: 1
Go Version: go1.10
Operating System: linux
GOPATH=
GOROOT=/usr/lib/go-1.10

开始创建以太坊私有链

初始化一个创世区块

初始化创世区块时，要先创建一个genesis.json文件，内容如下：
genesis.json：

{
  "config": {
        "chainId": 10,
        "homesteadBlock": 0,
        "eip155Block": 0,
        "eip158Block": 0
    },
  "coinbase"   : "0x0000000000000000000000000000000000000000",
  "difficulty" : "0x20000",
  "extraData"  : "",
  "gasLimit"   : "0x2fefd8",
  "nonce"      : "0x0000000000000042",
  "mixhash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "timestamp"  : "0x00",
  "alloc"      : {}
}

接下来，我们使用geth init ./genesis.json --datadir "./chain"命令，来进行创世区块的初始化，当前区块链网络数据存放的位置会保存在chain目录中：

wangzhen@wangzhen-VirtualBox:/opt/born$ geth init ./genesis.json --datadir "./chain"
INFO [04-19|16:16:55] Maximum peer count                       ETH=25 LES=0 total=25
INFO [04-19|16:16:55] Allocated cache and file handles         database=/opt/born/chain/geth/chaindata cache=16 handles=16
INFO [04-19|16:16:55] Writing custom genesis block 
INFO [04-19|16:16:55] Persisted trie from memory database      nodes=0 size=0.00B time=1.845µs gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [04-19|16:16:55] Successfully wrote genesis state         database=chaindata                      hash=5e1fc7…d790e0
INFO [04-19|16:16:55] Allocated cache and file handles         database=/opt/born/chain/geth/lightchaindata cache=16 handles=16
INFO [04-19|16:16:55] Writing custom genesis block 
INFO [04-19|16:16:55] Persisted trie from memory database      nodes=0 size=0.00B time=3.16µs  gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [04-19|16:16:55] Successfully wrote genesis state         database=lightchaindata                      hash=5e1fc7…d790e0

启用私有链

geth \
  --datadir "./chain" \
  --nodiscover \
  console 2>>eth_output.log

启动后的效果如下：

wangzhen@wangzhen-VirtualBox:/opt/born$ geth \
>   --datadir "./chain" \
>   --nodiscover \
>   console 2>>eth_output.log
Welcome to the Geth JavaScript console!

instance: Geth/v1.8.4-stable-2423ae01/linux-amd64/go1.10
 modules: admin:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

在当前目录执行tail -f eth_output.log，可以看到输出日志。

wangzhen@wangzhen-VirtualBox:/opt/born$ tail -f eth_output.log
INFO [04-19|16:18:29] Disk storage enabled for ethash DAGs     dir=/home/wangzhen/.ethash      count=2
INFO [04-19|16:18:29] Initialising Ethereum protocol           versions="[63 62]" network=1
INFO [04-19|16:18:29] Loaded most recent local header          number=0 hash=5e1fc7…d790e0 td=131072
INFO [04-19|16:18:29] Loaded most recent local full block      number=0 hash=5e1fc7…d790e0 td=131072
INFO [04-19|16:18:29] Loaded most recent local fast block      number=0 hash=5e1fc7…d790e0 td=131072
INFO [04-19|16:18:29] Regenerated local transaction journal    transactions=0 accounts=0
INFO [04-19|16:18:29] Starting P2P networking 
INFO [04-19|16:18:29] IPC endpoint opened                      url=/opt/born/chain/geth.ipc
INFO [04-19|16:18:29] Database deduplication successful        deduped=0
INFO [04-19|16:18:29] RLPx listener up                         self="enode://5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09@[::]:30303?discport=0"

后面章节中的命令，都是在启动私有链后的Geth javascript console中操作

帐户的添加和查看

查看帐户，可以看到当前帐户是空的

> web3.eth.accounts
[]
> 

创建帐户的方式有两种，第一种创建帐户时直接初始化密码

> web3.personal.newAccount("123456")
"0x25df465d9d9060423ce46137ca25aa5a10fd9a2f"

其中返回的0x25df465d9d9060423ce46137ca25aa5a10fd9a2f是帐户，123456是帐户的密码

第二种方法是先创建账户，然后输入密码

> web3.personal.newAccount()
Passphrase: 
Repeat passphrase: 
"0xd7b8a838f947adb4da47fa7208a2c177cfed6ab3"

这时我们再查看帐户，能够看到刚才创建的两个帐户已经存在了

> web3.eth.accounts
["0x25df465d9d9060423ce46137ca25aa5a10fd9a2f", "0xd7b8a838f947adb4da47fa7208a2c177cfed6ab3"]

开始挖矿和停止挖矿

挖矿执行以下命令：

 miner.start()

执行以后，通过刚才查看日志的方法tail -f eth_output.log,能够看到类似下面的日志，因为只有发送交易才会自动挖矿，所以会显示如下信息。

INFO [04-19|16:30:08] Commit new mining work                   number=1 txs=0 uncles=0 elapsed=175.12µs
INFO [04-19|16:30:16] Generating DAG in progress               epoch=0 percentage=0 elapsed=6.662s
INFO [04-19|16:30:23] Generating DAG in progress               epoch=0 percentage=1 elapsed=12.780s
INFO [04-19|16:30:29] Generating DAG in progress               epoch=0 percentage=2 elapsed=19.418s
INFO [04-19|16:30:35] Generating DAG in progress               epoch=0 percentage=3 elapsed=24.970s

需要在开发环境下，才能进行挖矿，修改上述命令为：

geth   --datadir "./chaindev"   --nodiscover    console 2>>eth_output.log  --dev --dev.period 1

挖矿执行以下命令：

 miner.start()

出现如下信息代表开始挖矿了

INFO [04-19|16:57:28] Successfully sealed new block            number=1 hash=eb3609…3747ef
INFO [04-19|16:57:28] 🔨 mined potential block                  number=1 hash=eb3609…3747ef
INFO [04-19|16:57:28] Commit new mining work                   number=2 txs=0 uncles=0 elapsed=417.68µs

挖矿会默认保存到创建的第一个帐户0x6426ea256ba1d45e966c9aabc0268594093251c4中。
block number=66，说明我们已经创建了66个区块
在以太坊官方的网络上，平均每15秒产生一个区块

停止挖矿执行以下命令：

> miner.stop()
true

停止挖矿后，以太币则不会产生，同样智能合约、转帐等操作也不会起作用。

查看帐户余额

查看帐户余额的方法如下：

> web3.eth.getBalance("0x6426ea256ba1d45e966c9aabc0268594093251c4")
1.15792089237316195423570985008687907853269984665640564039457584007913129639927e+77

以太币最小的单位是wei（18个0）

每次记一长串的地址很麻烦，我们可以通过设置变量来acc0表示帐户1

> acc0 = web3.eth.accounts[0]

"0x6426ea256ba1d45e966c9aabc0268594093251c4"

查看格式化的以太币

web3.fromWei(web3.eth.getBalance(acc0), 'ether')
1.15792089237316195423570985008687907853269984665640564039457584007913129639927e+59

因为geth javascript console是基于javascript的，所以也可以创建js函数，查看所有帐户余额

> function checkAllBalances() {
      var totalBal = 0;
      for (var acctNum in eth.accounts) {
         var acct = eth.accounts[acctNum];
         var acctBal = web3.fromWei(eth.getBalance(acct), "ether");
          totalBal += parseFloat(acctBal);
          console.log("  eth.accounts[" + acctNum + "]: \t" + acct + " \tbalance: " + acctBal + " ether");
      }
      console.log("  Total balance: " + totalBal + " ether");
  };

> checkAllBalances()
  eth.accounts[0]:  0x6426ea256ba1d45e966c9aabc0268594093251c4  balance: 1.15792089237316195423570985008687907853269984665640564039457584007913129639927e+59 ether
  eth.accounts[1]:  0x9e8e4b905e054575a7495a6822545da82f197b13  balance: 0 ether
  Total balance: 1.157920892373162e+59 ether

> 

如果命令较多，可以保存到一个脚本里，使用命令载入脚本：loadScript('/path/script/here.js')

转帐操作

从帐户0x6426ea256ba1d45e966c9aabc0268594093251c4转3个以太币到0x9e8e4b905e054575a7495a6822545da82f197b13,如果不指定单位ether，默认转的是wei。

>web3.eth.sendTransaction({from:acc0,to:acc1,value:web3.toWei(3,"ether")})
Error: authentication needed: password or unlock
    at web3.js:3104:20
    at web3.js:6191:15
    at web3.js:5004:36
    at <anonymous>:1:1

当直接执行此方法时会抛出异常，显示帐号被锁

执行开发者模式，创建的默认账户，不会报这个错误
如果报相关错误，执行以下语句

> web3.personal.unlockAccount(acc0,"123456")
true

转账完成的正确显示为:

web3.eth.sendTransaction({from:acc0,to:acc1,value:web3.toWei(3,"ether")})
"0x1c59a753ecd2efd7e916912df7bd8ae2973379df23024de9a3cee6ceb242b611"

但此时查看时会发现接收账户依旧为原来数值。此时需要执行挖矿命令，才会把转账真正完成。

> checkAllBalances()
  eth.accounts[0]:  0x6426ea256ba1d45e966c9aabc0268594093251c4  balance: 1.15792089237316195423570985008687907853269984665640564039457584007913129639927e+59 ether
  eth.accounts[1]:  0x9e8e4b905e054575a7495a6822545da82f197b13  balance: 0 ether
  Total balance: 1.157920892373162e+59 ether
undefined
> miner.start()
null
> checkAllBalances()
  eth.accounts[0]:  0x6426ea256ba1d45e966c9aabc0268594093251c4  balance: 1.15792089237316195423570985008687907853269984665640564039451584007913129639927e+59 ether
  eth.accounts[1]:  0x9e8e4b905e054575a7495a6822545da82f197b13  balance: 6 ether
  Total balance: 1.157920892373162e+59 ether
undefined
> miner.stop()
true

这里看到转账了6个币，是因为我执行了两次：）

添加节点

首先要知道自己的节点信息，在Geth命令行界面下输入命令,注意大小写

admin.nodeInfo

显示结果为：

> admin.nodeInfo
{
  enode: "enode://5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09@[::]:30303?discport=0",
  id: "5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09",
  ip: "::",
  listenAddr: "[::]:30303",
  name: "Geth/v1.8.4-stable-2423ae01/linux-amd64/go1.10",
  ports: {
    discovery: 0,
    listener: 30303
  },
  protocols: {
    eth: {
      config: {
        chainId: 10,
        eip150Hash: "0x0000000000000000000000000000000000000000000000000000000000000000",
        eip155Block: 0,
        eip158Block: 0,
        homesteadBlock: 0
      },
      difficulty: 131072,
      genesis: "0x5e1fc79cb4ffa4739177b5408045cd5d51c6cf766133f23f7cd72ee1f8d790e0",
      head: "0x5e1fc79cb4ffa4739177b5408045cd5d51c6cf766133f23f7cd72ee1f8d790e0",
      network: 1
    }
  }
}

其中

 enode: "enode://5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09@[::]:30303?discport=0"
 

就是自己节点的信息，注意要把“0.0.0.0“换成你自己的IP。将这个信息发送给其他节点，在其他节点的命令行中输入：

admin.addPeer("enode://5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09@192.168.1.121:30303?discport=0")

如果添加成功，输入admin.peers会显示出新添加的节点。

> admin.peers
[{
    caps: ["eth/63"],
    id: "5231f4677b0576292a6d7cd11890218ae2f84336338a4ce7b08e296aa3b9007c8dc728bf26b2e10a3de9afb4d5272ab13e86030a1e7db42474d6577aad174d09",
    name: "Geth/v1.8.4-stable-2423ae01/linux-amd64/go1.10",
    network: {
      inbound: false,
      localAddress: "192.168.1.112:42702",
      remoteAddress: "192.168.1.121:30303",
      static: true,
      trusted: false
    },
    protocols: {
      eth: {
        difficulty: 131072,
        head: "0x5e1fc79cb4ffa4739177b5408045cd5d51c6cf766133f23f7cd72ee1f8d790e0",
        version: 63
      }
    }
}]
> 

发送交易

解锁账户

> personal.unlockAccount(eth.accounts[0])


Unlock account 0x20869f8cb579e7712f60167d3d153d3f038960c9
Passphrase: 
true

发送交易

> eth.sendTransaction({from: "0x20869f8cb579e7712f60167d3d153d3f038960c9", to: "0x25df465d9d9060423ce46137ca25aa5a10fd9a2f", gas:31000, 'gasPrice': web3.toWei(300, 'gwei'), "value": "1"})
"0xe4ecfa81d367d2906e87a0f45b5bb90a0424f58bbd74d896ef217f3d5f132533"

此时交易已经提交到区块链，返回了交易的hash，但还未被处理，要使交易被处理，必须要挖矿。

交易成功后再对方账户上收到

> web3.fromWei(web3.eth.getBalance(eth.accounts[0]))
5.006300000000000001

参考资料

使用 Go-Ethereum 1.7.2搭建以太坊私有链
以太坊执行miner.start返回null终极解决方案
Geth官方安装指南
以太坊私链demo，实现第一笔交易
以太坊中的账户、交易、Gas和区块Gas Limit