The Ethereum Project provides an open-source, distributed, blockchain-based platform for so-called smart contracts.

Go Ethereum, the official Go implementation of the Ethereum protocol, is available as the go-ethereum package.

Create an account with geth account new.

The client can be started with geth, and it will proceed to download several gigabytes of blockchain data. This will take a very long time. This time can be shortened with

$ geth --syncmode full --cache=1024

Higher cache values appear to speed up the process more[1].

Optionally, start the client with geth console to get a JavaScript console for more meaningful interaction. This console can then be attached-to from another terminal or remotely with geth attach [hostname:port defaults to localhost].

To check balances in the console or attach modes, use web3.fromWei(eth.getBalance(eth.coinbase), "ether").

To start CPU mining, use geth --mine. This is far less efficient than GPU mining, and ethereum.org does not recommend it.

GPU mining with geth has been discontinued.

You can install the Ethereum Wallet via the mycrypto-bin^AUR package.