Before you start playing with Bitcoin, you should ensure that everything is setup correctly.
We suggest creating some aliases to make it easier to use Bitcoin.
You can do so by putting them in your .bash_profile, .bashrc or .profile.
cat >> ~/.bash_profile <<EOF
alias btcdir="cd ~/.bitcoin/" #linux default bitcoind path
alias bc="bitcoin-cli"
alias bd="bitcoind"
alias btcinfo='bitcoin-cli getwalletinfo | egrep "\"balance\""; bitcoin-cli getnetworkinfo | egrep "\"version\"|connections"; bitcoin-cli getmininginfo | egrep "\"blocks\"|errors"'
EOF
After you enter these aliases you can either source .bash_profile to input them or just log out and back in.
Note that these aliases includes shortcuts for running bitcoin-cli, for running bitcoind, and for going to the Bitcoin directory. These aliases are mainly meant to make your life easier. We suggest you create other aliases to ease your use of frequent commands (and arguments) and to minimize errors. Aliases of this sort can be even more useful if you have a complex setup where you regularly run commands associated with Mainnet, with Testnet, and with Regtest, as explained further below.
With that said, use of these aliases in this document might accidentally obscure the core lessons being taught about Bitcoin, so the only alias directly used here is btcinfo because it encapsulates much longer and more complex command. Otherwise, we show the full commands; adjust for your own use as appropriate.
You'll begin your exploration of the Bitcoin network with the bitcoin-cli command. However, bitcoind must be running to use bitcoin-cli, as bitcoin-cli sends JSON-RPC commands to the bitcoind. If you used our standard setup, bitcoind should already be up and running. You can double check by looking at the process table.
$ ps auxww | grep bitcoind
standup 455 1.3 34.4 3387536 1392904 ? SLsl Jun16 59:30 /usr/local/bin/bitcoind -conf=/home/standup/.bitcoin/bitcoin.conf
If it's not running, you'll want to run /usr/local/bin/bitcoind -daemon by hand and also place it in your crontab.
You should have the whole blockchain downloaded before you start playing. Just run the bitcoin-cli getblockcount alias to see if it's all loaded.
$ bitcoin-cli getblockcount
1772384
That tells you what's loaded; you'll then need to check that against an online service that tells you the current block height.
📖 What is Block Height? Block height is the the distance that a particular block is removed from the genesis block. The current block height is the block height of the newest block added to a blockchain.
You can do this by looking at a blocknet explorer, such as the Blockcypher Testnet explorer. Does its most recent number match your getblockcount? If so, you're up to date.
If you'd like an alias to look at everything at once, the following currently works for Testnet, but may disappear at some time in the future:
$ echo "alias btcblock='echo \$(bitcoin-cli -testnet getblockcount)/\$(curl -s https://blockstream.info/testnet/api/blocks/tip/height)'" >> .bash_profile
$ source .bash_profile
$ btcblock
1804372/1804372
🔗 TESTNET vs MAINNET: Remember that this tutorial generally assumes that you are using testnet. If you're using the mainnet instead, you can retrieve the current block height with:
curl -s https://blockchain.info/q/getblockcount. You can replace the latter half of thebtcblockalias (after/\$() with that.
If you're not up-to-date, but your getblockcount is increasing, no problem. Total download time can take from an hour to several hours, depending on your setup.
TESTNET vs MAINNET: When you set up your node, you choose to create it as either a Mainnet, Testnet, or Regtest node. Though this document presumes a testnet setup, it's worth understanding how you might access and use the other setup types — even all on the same machine! But, if you're a first-time user, skip on past this, as it's not necessary for a basic setup.
The type of setup is mainly controlled through the ~/.bitcoin/bitcoin.conf file. If you're running testnet, it probably contains this line:
testnet=1
If you're running regtest, it probably contains this line:
regtest=1
However, if you want to run several different sorts of nodes simultaneously, you should leave the testnet (or regtest) flag out of your configuration file. You can then choose whether you're using the mainnet, the testnet, or your regtest every time you run bitcoind or bitcoin-cli.
Here's a set of aliases that would make that easier by creating a specific alias for starting and stopping the bitcoind, for going to the bitcoin directory, and for running bitcoin-cli, for each of the mainnet (which has no extra flags), the testnet (which is -testnet), or your regtest (which is -regtest).
cat >> ~/.bash_profile <<EOF
alias bcstart="bitcoind -daemon"
alias btstart="bitcoind -testnet -daemon"
alias brstart="bitcoind -regtest -daemon"
alias bcstop="bitcoin-cli stop"
alias btstop="bitcoin-cli -testnet stop"
alias brstop="bitcoin-cli -regtest stop"
alias bcdir="cd ~/.bitcoin/" #linux default bitcoin path
alias btdir="cd ~/.bitcoin/testnet" #linux default bitcoin testnet path
alias brdir="cd ~/.bitcoin/regtest" #linux default bitcoin regtest path
alias bc="bitcoin-cli"
alias bt="bitcoin-cli -testnet"
alias br="bitcoin-cli -regtest"
EOF
For even more complexity, you could have each of your 'start' aliases use the -conf flag to load configuration from a different file. This goes far beyond the scope of this tutorial, but we offer it as a starting point for when your explorations of Bitcoin reaches the next level.
Before you start playing with bitcoin, you should make sure that your aliases are set up, your bitcoind is running, and your blocks are downloaded. You may also want to set up some access to alternative Bitcoin setups, if you're an advanced user.
Continue "Understanding Your Bitcoin Setup" with §3.2: Knowing Your Bitcoin Setup.