feat(send-transaction): improve subject

subjects/blockchain/send-transaction/README.md

@@ -1,38 +1,72 @@
-# Send Transaction
+## send-transaction
 
 The purpose of this exercise is to create a simple Bitcoin transaction locally using the command line. As we use new tools this exercise is guided.
 
 ### Instructions
 
 - Install a Bitcoin node. There are two solutions :
+
   - Use a preconfigured image for a virtual machine such as [cryptotux](https://cryptotux.org/)
-  - Install manually by downloading and installing the Bitcoin Core software from [github](https://github.com/bitcoin/bitcoin/releases).
-- Launch Bitcoin core daemon on _regtest_ network. You can do so with `bitcoind -regtest -fallbackfee=0.00000003` assuming the executable is in your shell's path.
+  - Install manually by downloading and installing the Bitcoin Core software from [GitHub](https://github.com/bitcoin/bitcoin/releases).
+
+```console
+export bitcoinCoreVersion="24.0.1"
+wget -q "https://bitcoincore.org/bin/bitcoin-core-$bitcoinCoreVersion/bitcoin-$bitcoinCoreVersion-x86_64-linux-gnu.tar.gz"
+tar xzf "bitcoin-$bitcoinCoreVersion-x86_64-linux-gnu.tar.gz"
+sudo mv bitcoin-$bitcoinCoreVersion/bin/* /usr/local/bin
+rm -rf bitcoin-$bitcoinCoreVersion/
+rm "bitcoin-$bitcoinCoreVersion-x86_64-linux-gnu.tar.gz"
+```
+
+- Launch Bitcoin core daemon on _regtest_ network. You can do so with the following command assuming the executable is in your shell's path.
+
+```console
+$ bitcoind -chain=regtest -daemon -fallbackfee=0.00000003
+$
+```
+
 - Create manually a wallet and two addresses on _Bitcoin regtest_. You may do this by running the following commands
-  ```bash
-  bitcoin-cli createwallet "testwallet"
-  bitcoin-cli getnewaddress
-  bitcoin-cli getnewaddress
-  ```
-- Generate 101 blocks to get fresh bitcoins. You need 101 blocks as the Bitcoin you receive from mining are locked for 100 blocks.
-  You may use the following command `bitcoin-cli -regtest generatetoaddress 101 <your address>`
+
+```console
+$ bitcoin-cli -regtest createwallet "testwallet"
+...
+$ bitcoin-cli -regtest getnewaddress
+...
+$ bitcoin-cli -regtest getnewaddress
+...
+$
+```
+
+- Generate 101 blocks to get fresh bitcoins. You need 101 blocks as the Bitcoin you receive from mining are locked for 100 blocks. You may use the following command:
+
+```console
+$ bitcoin-cli -regtest generatetoaddress 101 <your address>
+...
+$
+```
 
 - Send a transaction of 2 bitcoins to the second address.
 
-- List the last transactions `bitcoin-cli listtransactions`
-- Create a js file and exports the hash of your transaction in a variable `txid`.
+```console
+$ bitcoin-cli -regtest sendtoaddress <the second address> 2
+...
+$
+```
 
-### Usage
+- List the last transactions
 
-```js
-exports.txid =
-  "be3d0d245e7dce50964ac9157aee7e18a3828e11d89f72ee0bc3f76b526e5bb";
+```console
+$ bitcoin-cli -regtest listtransactions
+...
+$
 ```
 
+- Create a JS file `send-transaction.js` with a variable `txid` that will store the hash of your transaction. The variable `txid` needs to be importable from an external file!
+
 Congrats for your first Bitcoin transaction!
 
 ### Notions
 
-- A linux image with developer tools [cryptotux.org](https://cryptotux.org/)
 - Bitcoin core node [bitcoin.org](https://bitcoin.org/)
-- Send to address [reference](https://wbnns.github.io/bitcoin-dev-docs/reference/rpc/sendtoaddress.html)
+- [Bitcoin for developers introduction](https://wbnns.github.io/bitcoin-dev-docs/examples/intro.html)
+- A Linux image with developer tools [cryptotux.org](https://cryptotux.org/)