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Now, the first thing we're going to do is open up a Terminal. And inside Terminal, we're going to navigate
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to our desktop.
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So if you're not familiar with the command line and you haven't watched the module on the command line,
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then I recommend you to take a look at it now because we're going to be using a lot of the commands
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to create directories and navigate around.
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So if you're not yet familiar, then it's a good time to take a look at that.
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So the first thing I'm going to do is I'm going to cd into my desktop. And here, I'm going to create a
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a new directory called Story. Then I'm going to CD into this Story directory. And if I show you with "ls,"
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you can see that it's completely empty.
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And similarly, inside Finder, I can show you the same thing.
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So let's go ahead and create some text files.
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So I'm going to use touch to create a file called chapter1.txt and then I'm going to open chapter1.txt,
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and you can either do this by simply writing open and it'll open it inside the default application
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which is TextEdit on a Mac.
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Alternatively, you can use a text that's within the Terminal, for example, vim.
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Now, this is only for people who are really familiar with this.
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So it's totally up to you what you decide to use.
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But if you are not familiar with using Terminal-based editors, then it's probably a good idea to just
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stick with the open command and use TextEdit.
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So let's go ahead and open chapter1 and let's write something inside, shall we?
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Okay.
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So there's my masterpiece done.
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I'm going to go ahead and hit save and I'm going to quit TextEdit.
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So that was our first chapter done.
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So, now let's create a Git local repository and start tracking some of these file changes.
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So to initialize Git, we simply write "git init."
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And as you can see, it's initialized and empty Git repository inside the story directory.
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Now,  if you have a look inside Finder, you actually can't see this .git at all.
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But as we learned before,
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if you use ls -a,
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you can see all the hidden files and you can see that .git is right there and it's going to be used
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to track all your changes, to commit your changes, and to perform version control.
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So we're currently inside the story directory, and you can also call this the working directory.
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So as I mentioned before, using Git and learning about version control, it comes with some of its own terminology
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and language.
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So, I'm going to try and debunk and simplify a lot of these terms that you'll come across, just so that
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we can all be on the same page, and we all understand what's going on.
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So currently, we are inside the working directory which is the story directory.
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And here in order to start tracking the changes of my files,
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for example, chapter1.txt, then I need to add this file to what's called a staging area.
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And that is basically a intermediate place where you can pick and choose which files inside your working
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directory that you want to commit.
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So to see what's currently inside your staging area, you can use the Git status command, and it shows
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you that there are untracked files which will be shown in red, and this is something that simply inside
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a working directory,
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so inside here,
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but it's not yet in the staging area.
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So in order to add it to the staging area and to start tracking changes in it, then we have to use the
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command "git add."
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So we're going to type git add and we're going to type the filename,
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so in this case, it's chapter1.txt.
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So go ahead and hit enter. And then if we try using Git status again, you can see that that file has been
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added as a new file and it is now green.
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So this is now in the staging area and it's ready to be committed.
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So let's go ahead and commit this under version control.
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So the command is git commit and I'm going to use the -m flag to add a commit message.
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So the commit message is really really important.
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It's something that helps you keep track of what changes you have made in each commit.
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So when you create a new save point, you want to be as explicit as possible about what changes were made
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between the last save point and this current save point.
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So for our initial commit, we can use something very simple like "Initial Commit" and this shows that this
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is our starting point.
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Alternatively, if you want to be slightly more specific, because in our case, we've actually completed
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Chapter 1.
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So you can write "Complete Chapter 1."
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Now, the thing that you'll realize is that usually with commit messages, they are written in the present
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tense,
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and this is the best practice.
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So whereas it would probably make more sense, I guess, at least in my head anyways to write "Completed
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Chapter 1" as this save point.
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It's actually by convention that you should always use the present tense.
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So it's like you are doing it now. You're submitting your changes now.
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So let's go ahead and hit enter to make our first commit. And you can see what commits you have made
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by using the git log command.
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So you can see that this commit was made at this time by this person.
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And it also has a hash and this hash uniquely identifies this particular commit.
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And then right at the end, you see this commit message of what this save point was all about.
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So, now I'm going to go ahead and create two more chapters.
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So let's just create chapter2.txt and chapter3.text. And now we have three chapters
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and I'm going to go in and change some of these text files.
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So let's say...
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Okay, so that's Chapter 2 done.
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And finally, let's go ahead and just open chapter3 and edit that as well.
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All right.
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So all three files have been changed.
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And over here in Finder, you can actually get a quick peek at what the contents are which is going to
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be really useful for me to be able to demonstrate to you what Git is doing behind the background.
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So, now let's go ahead and add these two new files to our staging areas.
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So, again, if we use Git status, you can see that there's two files that are untracked which are only in
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the working directory, and not yet inside the staging area.
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So we can put it into the staging area by simply adding each of them as we did before,
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"git add," and writing something like chapter2.txt, 
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and then doing git add chapter3.text.
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But as you can imagine, if you have quite a few files, then it can get incredibly tedious having to do
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this one by one.
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So, of course, there is a better way.
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So instead of adding these files one by one, we can actually simply just say git add and then use the
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dot to specify everything inside this current directory.
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So everything inside the story directory.
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So, now if I go ahead and hit enter and then let's go to git status again,
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you can see that the two new files that have been added to the staging area. And now we're going to commit
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those two files to a new commit to a new save point.
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And you know what to do if you're following along with me,
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go ahead and give it a go.
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All right.
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So how was that? If you remember, the command is gt to commit and we're going to use -m flag
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to specify a commit message, and we're going to write a message that is in the present tense. So let's
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say, "complete chapter 2 and 3."
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So that's everything I've done between the initial commit and this commit.
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The only difference is the fact that I've completed now Chapter 2 and Chapter 3.
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So let's go ahead and and hit enter.
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So, again, let's check it out using Git log.
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We can see that we now have two commits, both with different hashes because they are unique and they
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are different.
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So the initial one was "Complete Chapter 1" and it was done at this time. And then later on, about five
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minutes later, I completed Chapter 2 and 3.
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And that was the second commit.
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And this is where we are at right now.
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So you can see by the HEAD, by this word "HEAD," this is the position or the current state that we are in.
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So I just want to quickly recap what we've just done.
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So we created a file in our working directory inside our story directory.
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So the working directory is the folder or the directory where you initialize your Git repository.
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When we said "git init," we did that inside the story directory,
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so that becomes a working directory.
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And from now on, Git is going to try and track the changes that it sees between the working directory
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and the local repository.
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So in the beginning, we created a file inside our working directory, inside the story, and then we used
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"git add" to push it to the staging area.
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Now, the reason why there is this intermediate staging area because you might wonder, why not just go
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from the working directory straight to the repository,
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why do we need this extra step?
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Well, sometimes you might not want to add all of your files to be tracked or all of your files to be
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committed.
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So the staging area is a good place to try and figure out what are the things that you want Git to ignore
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and what are the things that you want to be tracked.
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So once we've used "git add," we've put out file into the staging area and we're happy with the changes
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that we are going to commit, then the next step is to go ahead and commit it using the "git commit" command.
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So, now our file is inside our local repository, so that .git, and that version is given a name through
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the commit message.
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So that means that even if we've messed up our file, we can still use the last version that's under version
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control and we can use a special command called "git checkout" to revert back or roll back to the last
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position in our local repository.
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So let me show you what that looks like in the command line and how we would do that in practice.
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So at the moment, I've got three nicely written chapters, and I have a feeling my book is going to be
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a big seller.
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So, now let's say that I have, you know, I've been working on Chapter 3 and I have completely messed
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everything up, and I'm just, you know, fell asleep on my keyboard, and I happened to have saved my file.
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And now if you have a look at it, it's now just mumbo jumbo and I've ruined my masterpiece.
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But fear not because we have version control and we have Git enabled,
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so we have nothing to worry about.
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I can actually revert the changes that I've made locally in my working directory.
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So at this point, you can use "gIt status" to see that we have modifications in our chapter3.txt file
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that have not yet been committed or added to the staging area.
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So if we wanted to, we can actually revert this back to its previous glory.
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But before we do that, we can use a Git command to check out what are the differences between the current
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version of Chapter 3 and the last save point in our Git repository.
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So to do that, you can use the command "git diff,"
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so the difference, and we'll give it the chapter3 file name.
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And if you hit enter, you can see that this is the part that was deleted,
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so the part in red. And then this was the part that was added which is our gobbledygook.
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So, now if I've looked at these differences, it might just be that, you know, there's only a few mistakes
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in my new version of Chapter 3 and I just want to maybe copy some things over or have a look at how I did
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certain things previously, and change my current file.
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But other times, it might be that, you know, it's just you want to torch the new file,
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you just don't want anything to do with it,
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and you would much rather roll back to the previous version.
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So if you want to do that, then there is a command called "git checkout" that is going to be really, really
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useful for you.
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So git checkout.
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And then we're going to specify the name of the file that we want to check out which is chapter3.txt.
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And if you just watch over here which is the preview of the current version of chapter3.txt,
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once I hit enter on this command that basically asks to roll back this Chapter 3 to the last version
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that was committed in our local repository.
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So if I hit enter, you can see that almost immediately my Chapter 3 has been restored to its previous
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glorious state, and this is the version of chapter 3 at the last checkpoint at which I committed it.
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So that was this one which is completed Chapter 2 and 3.
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So whereas in this lesson, we've looked mostly at local implementations of Git,
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so saving these versions on our computer locally. In the next lesson, I'm going to talk about GitHub
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and creating remote repositories. So I'll see you there.