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In this video, I'll explain Git. So what is Git? Git is a distributed version control

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system. It's not a part of Linux. From now on, we will be talking about items that are

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not a direct part of Linux, but it is often used in Linux environment. And fun fact, Git

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has been created by Linus Torvalds, who is also the creator of the Linux kernel. Linus

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created Git because he needed something to work together in an efficient way with multiple

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people. So in Git, developers can work in products together where each file revision

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is stored in the system. Old versions of files are always available and a log is maintained

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of who made which change to which files. And Git is distributed because it allows the developers

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to work offline after cloning a remote repository locally. Now, Git works with a repository

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which can contain different development branches. And developers as well as users can easily

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upload as well as download new files to and from the Git repository. And to do so, a Git

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client is needed. And this Git client in Linux typically is the Git command, but other Git

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clients are available as well. There are different Git platforms. GitHub is a very common platform.

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GitLab is a common alternative. But private Git servers can also be hosted. No matter

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how you host it, it always works in the same way. Now let's try to understand the Git workflow.

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After cloning, the developer makes changes to the working tree. And all changes are made

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to the local repository, the locally cloned repository. And that means that the developer

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changes are not immediately visible to the entire community. Once a developer is happy,

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the developer can push changes to the remote repository. And if the local repository is

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network accessible, the owner of the repository can pull changes from it. Now in Git, different

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trees are used to work with the state of the file. There are three of them. The trees are

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stored as files in the .git directory. You don't normally see them, but it is nice to

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understand how it works to understand the workflow in Git. So there is the working directory,

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which holds the actual files. Then there is the index, which acts as a staging area. And

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the head points to the last commit that was made. When you are working with Git, you start

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with git add. Git add is used to add files to the index. To commit these files to the head,

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you use git commit minus m commit message. And that is what the developer would normally do

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when they are happy with the file that was created. Also, at some point, the local repository

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needs to be connected to the remote repository. If that hasn't been done already, you need

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git add origin HTTPS colon slash slash server slash repo name to connect to the remote repository.

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So on the Git client, you always need to add the remote repository using git remote add origin

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HTTPS colon slash slash server name slash repo name. And once you have done that, you can complete

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the sequence and use git push origin master, where master is replaced with the actual branch

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name that you want to push the changes to. Let me make a quick drawing to visualize this process.

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Let's try to understand the Git workflow. It all starts at the Git server. And on the Git server,

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you have your Git repository. So you need to be able that this Git repository is getting to the

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Git client. Well, it depends a little bit on how you want to work. But one of the things that you

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can do is a simple Git clone. And Git clone is initializing the data from the Git server to the

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Git client. You can also do a Git init on the client if it's not yet known, and you need to

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push data to the Git server. Now on the Git client, you'll start working. And in order to work,

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you have your working directory. And in the working directory, nothing is synchronized

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with Git yet. In order to synchronize data, you first need to put it into the index.

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And then you need to put it into the head. And there are three different phases in your work

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with Git that are relevant. The first thing is where you are going to use the git add command.

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So git add is adding your changes from the working directory to the index. And then you are going to

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use git commit to commit your changes to the head. And once the changes are ready in the head,

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then you are going to use git push. And git push is going to push the changes swap all the way

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to the Git repository. Now it is possible that in the meantime, somebody else has made changes as

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well. And if that is happening, well, you also need to have git pull and git merge. We will talk

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about those in upcoming videos. Now final thing I want to tell you about is file states. So files

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in Git can be in different states. And the git status command can be used to request the current

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file state. Three states. There is modified. Modified means that the file in the working

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tree is different from the file in the repository. There is staged, which means that the modified

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file was added to a list of changed files in the index. And committed, that means that the modified

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file has been committed to the head and is ready to be pushed. So the only thing remaining is git

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push to make sure that the file is shared with the community.