Learning-Bitcoin-from-the-Command-Line/A3_2_Mining_with_Regtest.md

A3.2: Mining the Regtest

NOTE: This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.

This document explains how to generate (i.e. mine) blocks using a Regtest (Regression Test) blockchain. To generate blocks on a new blockchain requires very minimal proof-of-work and it will take less than a second, due to the low difficulty and because it follows the Testnet rules.

Generating blocks

You can generate (mine) new blocks on a regtest chain using the RPC method generate with an argument of how many blocks to generate. It only makes sense to use this method on regtest; due to the high difficulty it's very unlikely that it will yield to new blocks in the mainnet or testnet:

$ bitcoin-cli -regtest generate 101
[
  "57f17afccf28b9296048b6370312678b6d8e48dc3a7b4ef7681d18ed3d91c122",
  "631ff7b8135ce633c774828be3b8505726459eb65c339aab981b10363befe5a7",
  ...
  "1162dbfe025c7da94ee1128dc26d518a94508f532c19edc0de6bc673a909d02c",
  "20cb2e815c3d42d6a117a204a0b5e726ab641c826e441b5b3417aca33f2aba48"
]

Because a block must have 100 confirmations before that reward can be spent, we generate 101 blocks, providing access to the coinbase transaction from block #1. Because this is a new block chain using Bitcoin’s default rules, the first blocks pays a block reward of 50 bitcoins. Unlike mainnet, in regtest mode only the first 150 blocks pay a reward of 50 bitcoins. The reward halves after 150 blocks, so it pays 25, 12.5, and so on...

The output is the block hash of every block generated.

What's Next?

After starting your bitcoind on regtest and generating the first blocks, you have balance in your address to spend and test using Regtest blockchain.