Merge branch 'master' into AbuShafrah-review

Author: shannona

01_0_Introduction.md

@@ -6,7 +6,7 @@ The ways that we make payments for goods and services has been changing dramatic
 
 These centralization risks were some of the prime catalysts behind the creation of cryptocurrencies, the first and most successful of which is Bitcoin. Bitcoin offers pseudonymity; it makes it difficult to correlate transactions; and it makes censorship by individual entities all but impossible. These advantages have made it one of the quickest growing currencies in the world. That growth in turn has made Bitcoin into a going concern among entrepreneurs and developers, eager to create new services for the Bitcoin community.
 
-If you're one of those entrepreneurs or developers, then this course is for you, because it's all about learning to program Bitcoin. It's an introductory course that explains all the nuances and features of Bitcoin as it goes. It also takes a very specific tack, by offering lessons in how to work _directly_ with Bitcoin Core and with the c-lightning server using their RPC interfaces.
+If you're one of those entrepreneurs or developers, then this course is for you, because it's all about learning to program Bitcoin. It's an introductory course that explains all the nuances and features of Bitcoin as it goes. It also takes a very specific tack, by offering lessons in how to work _directly_ with Bitcoin Core and with the core lightning server using their RPC interfaces.
 
 Why not use some of the more fully featured libraries found in various programming languages? Why not create your own from scratch? It's because working with cryptocurrency is dangerous. There are no safety nets. If you accidentally overpay your fees or lose a signing key or create an invalid transaction or make any number of potential mistakes, then your cryptocurrency will be gone forever. Much of that responsibility will, of course, lie with you as a cryptocurrency programmer, but it can be minimized by working with the most robust, secure, and safe cryptocurrency interfaces around, the ones created by the cryptocurrency programming teams themselves: ``bitcoind`` and ``lightningd``.
 

01_1_Introducing_Bitcoin.md

@@ -80,7 +80,7 @@ Though you need to understand the basics of how a blockchain works to understand
 
 **_Why Is It Called a Chain?_** Each block in the blockchain stores a hash of the block before it. This links the current block all the way back to the original "genesis block" through an unbroken chain. It's a way to create absolute order among possibly conflicting data. This also provides the security of blockchain, because each block is stacked atop an old one makes it harder to recreate the old block due to the proof-of-work algorithms used in block creation. Once several blocks have been built atop a block in the chain, it's essentially irreversible.
 
-**_What is a Fork?_** Occasionally two blocks are created around the same time. This temporarily creates a one-block fork, where either if the current blocks could be the "real" one. Every once in a while, a fork might expand to become two blocks, three blocks, or even four blocks long, but pretty quickly one side of the fork is determined to be the real one, and the other is "orphaned". This is part of the stochastic process of block creation, and demonstrates why several blocks must be built atop a block before it can be considered truly trustworthy and non-repudiable.
+**_What is a Fork?_** Occasionally two blocks are created around the same time. This temporarily creates a one-block fork, where either of the current blocks could be the "real" one. Every once in a while, a fork might expand to become two blocks, three blocks, or even four blocks long, but pretty quickly one side of the fork is determined to be the real one, and the other is "orphaned". This is part of the stochastic process of block creation, and demonstrates why several blocks must be built atop a block before it can be considered truly trustworthy and non-repudiable.
 
 ### Blockchain — In Short
 
@@ -123,7 +123,7 @@ Lightning is a layer-2 protocol that interacts with Bitcoin to allow users to ex
 
 Lightning is also the secondary focus of this tutorial. Though it's mostly about interacting directly with Bitcoin (and the `bitcoind`), it pays some attention to Lightning because it's an upcoming technology that is likely to become a popular alternative to Bitcoin in the near future. This book takes the same approach to Lightning as to Bitcoin: it teaches how to interact directly with a trusted Lightning daemon from the command line.
 
-Unlike with Bitcoin, there are actually several variants of Lightning. This tutorial uses the standard-compliant [c-lightning](https://github.com/ElementsProject/lightning) implementation as its trusted Lightning server.
+Unlike with Bitcoin, there are actually several variants of Lightning. This tutorial uses the standard-compliant [core lightning](https://github.com/ElementsProject/lightning) implementation as its trusted Lightning server.
 
 **_What is a Layer-2 Protocol?_** A layer-2 Bitcoin protocol works on top of Bitcoin. In this case, Lightning works atop Bitcoin, interacting with it through smart contracts.
 

04_2__Interlude_Using_JQ.md

@@ -372,7 +372,7 @@ $ usedtxid=($(bitcoin-cli decoderawtransaction $rawtxhex | jq -r '.vin | .[] | .
 $ usedvout=($(bitcoin-cli decoderawtransaction $rawtxhex | jq -r '.vin | .[] | .vout'))
 $ btcin=$(for ((i=0; i<${#usedtxid[*]}; i++)); do txid=${usedtxid[i]}; vout=${usedvout[i]}; bitcoin-cli listunspent | jq -r '.[] | select (.txid | contains("'${txid}'")) | select(.vout | contains('$vout')) | .amount'; done | awk '{s+=$1} END {print s}')
 $ btcout=$(bitcoin-cli decoderawtransaction $rawtxhex | jq -r '.vout  [] | .value' | awk '{s+=$1} END {print s}')
-$ echo "$btcin-$btcout"| /usr/bin/bc
+$ echo $(printf '%.8f-%.8f' $btcin $btcout_f) | /usr/bin/bc
 .255
 ```
 And that's also a good example of why you double-check your fees: we'd intended to send a transaction fee of 5,000 satoshis, but sent 255,000 satoshis instead. Whoops!

05_3_Funding_a_Transaction_with_CPFP.md

@@ -82,7 +82,7 @@ $ bitcoin-cli getrawtransaction 95d51e813daeb9a861b2dcdddf1da8c198d06452bbbecfd8
 ```
 Look through the `vout` array. Find the object that matches your address. (Here, it's the only one.) The `n` value is your `vout`. You now have everything you need to create a new CPFP transaction.
 ```
-$ utxo_txid=2NFAkGiwnp8wvCodRBx3smJwxncuG3hndn5
+$ utxo_txid=95d51e813daeb9a861b2dcdddf1da8c198d06452bbbecfd827447881ff79e061
 $ utxo_vout=0
 $ recipient2=$(bitcoin-cli getrawchangeaddress)
 ```

11_1_Understanding_Timelock_Options.md

@@ -19,7 +19,7 @@ In more recent years, Bitcoin Core has expanded to allow the manipulation of tim
 
 _They Are Opcodes._ Because they're opcodes, CLTV and CSV can be used as part of more complex redemption conditions. Most often they're linked with the conditionals described in the next chapter.
 
-_They Lock Outputs._ Because they're opcodes that are included in transactions as part of a `sigPubKey`, they just lock that single output. That means that the transactions are accepted onto the Bitcoin network and that the UTXOs used to fund those transactions are spent. There's no going back on a transaction timelocked with CLTV or CSV like there is with a bare `nLockTime`. Respending the resultant UTXO then requires that the timelock conditions be met.
+_They Lock Outputs._ Because they're opcodes that are included in transactions as part of a `scriptPubKey`, they just lock that single output. That means that the transactions are accepted onto the Bitcoin network and that the UTXOs used to fund those transactions are spent. There's no going back on a transaction timelocked with CLTV or CSV like there is with a bare `nLockTime`. Respending the resultant UTXO then requires that the timelock conditions be met.
 
 Here's one catch for using timelocks: _They're one-way locks._ Timelocks are designed so that they unlock funds at a certain time. They cannot then relock a fund: once a timelocked fund is available to spend, it remains available to spend.
 

11_3_Using_CSV_in_Scripts.md

@@ -14,7 +14,7 @@ Easy!
 
 > :information_source: **NOTE — SEQUENCE:** This is the third use of the `nSequence` value in Bitcoin. Any `nSequence` value without the 32nd bit set (1<<31), so 0x00 00 00 01 to 0x7f ff ff ff, will be interpreted as a relative timelock if `nVersion ≥ 2` (which is the default starting in Bitcoin Core 0.14.0). You should be careful to ensure that relative timelocks don't conflict with the other two uses of `nSequence`, for signalling `nLockTime` and RBF. `nLockTime` usually sets a value of 0xff ff ff ff-1, where a relative timelock is disallowed; and RBF usually sets a value of "1", where a relative timelock is irrelevent, because it defines a timelock of 1 block. 
 
-> In general, remember: with a `nVersion` value of 2, a `nSequence` value of 0x00 00 00 01 to 0x7f ff ff ff allows relative timelock, RBF, and `nLockTime`; a `nSequence` value of 0x7f ff ff ff to 0xff ff ff ff-2 allows RBF and `nLockTime`; a `nSequence` value of 0xff ff ff ff-1 allows only `nLockTime`; a `nSequence` value of 0xff ff ff ff allows none; and `nVersion` can be set to 1 to disallow relative timelocks for any value of `nSequence`. Whew!
+> In general, remember: with a `nVersion` value of 2, a `nSequence` value of 0x00000001 to 0x7ffffff allows relative timelock, RBF, and `nTimeLock`; a `nSequence` value of 0x7fffffff to 0xffffffff-2 allows RBF and `nTimeLock`; a `nSequence` value of 0xffffffff-1 allows only `nTimeLock`; a `nSequence` value of 0xffffffff allows none; and `nVersion` can be set to 1 to disallow relative timelocks for any value of `nSequence`. Whew!
 
 ### Create a CSV Relative Block Time
 

19_0_Understanding_Your_Lightning_Setup.md

@@ -2,13 +2,13 @@
 
 > :information_source: **NOTE:** This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.
 
-The previous chapter concluded our work with Bitcoin proper, through CLI, scripting, and programming languages. However, there are many other utilities within the Bitcoin ecosystem: this chapter and the next cover what may be the biggest and most important: the Lightning Network. Here you'll begin work with the `lightning-cli` command-line interface, understanding a c-lightning setup and its features, including some examples and basic configuration.
+The previous chapter concluded our work with Bitcoin proper, through CLI, scripting, and programming languages. However, there are many other utilities within the Bitcoin ecosystem: this chapter and the next cover what may be the biggest and most important: the Lightning Network. Here you'll begin work with the `lightning-cli` command-line interface, understanding a core lightning setup and its features, including some examples and basic configuration.
 
 ## Objectives for This Chapter
 
 After working through this chapter, a developer will be able to:
 
-   * Assess that a c-lightning Node is Installed and Up-to-date
+   * Assess that a core lightning Node is Installed and Up-to-date
    * Perform Basic Lightning Wallet Commands
    * Create a LIghtning Channel
 
@@ -20,7 +20,7 @@ Supporting objectives include the ability to:
 
 ## Table of Contents
 
-* [Section One: Verifying Your c-lightning Setup](19_1_Verifying_Your_Lightning_Setup.md)
-* [Section Two: Knowing Your c-lightning Setup](19_2_Knowing_Your_lightning_Setup.md)
+* [Section One: Verifying Your core lightning Setup](19_1_Verifying_Your_Lightning_Setup.md)
+* [Section Two: Knowing Your core lightning Setup](19_2_Knowing_Your_lightning_Setup.md)
    * [Interlude: Accessing a Second Lightning Node](19_2__Interlude_Accessing_a_Second_Lightning_Node.md)
 * [Section Three: Creating a Lightning Channel](19_3_Setting_Up_a_Channel.md)