To learn how Ethereum works and set up your own local Etnereum testnet, followed by an Ethereum Smart Contract.For much greater detail, see the .I used an Ubuntu 14.04 virtual machine.In a Web browser, go to Live data about Ethereum appears, as shown below.When I did it (7-7-16), there were 81 million Ethers, worth $10 each, for a total market capitalization around $800 M. This makes Ethereum the second largest cryptocurrency--only Bitcoin is larger, with a market cap of about $12 B.In the top center, hover the mouse over BLOCKCHAIN and click "View Pending Txns".A short list of pending transactions appears, as shown below.Refresh your browser every few seconds to see how it works--transactions accumulate for about 30 seconds, then vanish, as the block is mined.The time between blocks varies quite a bit--I saw one block as long as 1 minute.In the top section, hover the mouse over STATS and click "Block Count Chart".

A chart appears, as shown below.As you can see, Ethereum has approximately 6000 blocks per day -- approximately one every 30 seconds.In a Terminal window, execute these commands to install the Ethereum software: Execute these commands to make a genesis block: Paste in this code: Save the file with Ctrl+X, Y, Enter.Execute these commands to create the blockchain: In the geth console, execute this command to make a new account: Enter a password twice to see your account address, as shown below.Make a note of this address.Exit the geth console with: Execute this command to edit the genesis block: Edit the "alloc" secton to include your own address and a balance, as shown below.Save the file with Ctrl+X, Y, Enter.Execute these commands to clear out the old blockchain data and restart geth: In the geth console, execute these commands.Your address appears, and your balance of 10 Ether, as shown below.

Your blockchain isn't operating yet because it has no miners.First execute this command to exit the geth console: To start mining, execute this command: Geth starts, as shown below.Note: If you use Geth/v1.5.0-unstable, as shown in the image below, the project will fail.I modified the instructions so you should have a stable version 1.4.9 instead.Execute this commands to see your balance: You now have more than 10 Ether, as shown below.Our contract is written in the Solidity language.To use it, we need to install Solc, the Solidity compiler.Open a new Terminal window, to see a Bash prompt ($).Execute this command: A message appears saying "Press [ENTER} to continue.You see a path to solc.Make a note of it.In the figure below, the path is Return to the Terminal window showing the geth console.Execute these commands, adjusting the path in the first command to point to your solc location, if necessary.The response to the second command is , as shown below, indicating that the compiler is ready to use.

Here's the code for a very simple contract, with added comments.It contains two contracts: To launch the contract, you need to spend some Ether, so you must unlock your account.bitcoin 40000In the geth console, execute these commands: Enter your password.bitcoin to aud calculatorAfter a pause of several seconds, the response is "true", as shown below.litecoin news 2014In the geth console, copy and paste in this command.bitcoin tor setupIt includes the whole source code of your contract, without comments, on one line.bitcoin peso valueOnly the end of the code is visible, and the reply is "undefined", as shown below.bitcoin hitman

In the geth console, execute this command.The reply is "undefined" again, as shown below.You have defined two contract object types, and .Now you need to define the greeting message and launch a specific instance of the object.bitcoin rig buyThis will require you to spend some Ether.btc china accept bitcoin(We're using a test blockchain, so the Ether won't cost any real money.)bitcoin baccaratIn the geth console, paste in these commands.A "Contract transaction send" message appears, and after a few seconds, you see "Contract mined!", as shown below.In the geth console, execute these commands.The first command returns a long address, and the second one returns "Hello World!", as shown below.The Application Binary Interface is "a sort of user manual, describing the name of its functions and how to call them", according to the .

To see it, execute this command: The object has two methods defined by its source code: "kill" and "greet", and a "constructor" (which is automatically called when an instance of the object is created), as shown below.To make the greeter contract available to other machines on your Ethereum network, you need to create a Javascript object for them to call.Execute this command, all on one line.Replace the address at the end with the your greeter's address, which you noted earlier.Only a portion of that long command is visible, and the response is "undefined", as shown below.To see the methods and attributes of the "greeter2" object, execute this command: It has the same two methods: "kill" and "greet", a constructor, and the address you specified, as shown below.To run the greet method of the greeter2 object, execute this command: The reply is "Hello World!", as shown below.The Ethereum blockchain has abandoned contracts on it, which is wasteful.