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- Let's talk about Git.

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Git is a distributed
version control system.

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It allows developers to
work in products together,

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where each file revision
is stored in the system.

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Old versions of files
are always available,

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and the log is maintained

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of who made what change to which file.

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Git is distributed

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because it allows
developers to work offline

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after cloning a remote repository locally,

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and that makes it a very popular platform.

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Git works with a repository,

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which can contain different
development branches.

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Developers and users can
easily upload as well

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as download new files to
and from the Git repository,

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and in order to do so,
a Git client is needed.

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Git clients are available
for all operating system.

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No matter if you work on
Windows, Mac, or Linux,

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you'll find a Git client.

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At the other end there's the Git platform.

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GitHub is a very common platform,

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GitLab is a common alternative,

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and private Git servers
can also be hosted.

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In this lesson, I'll
be focusing on GitHub,

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because it's the most common platform

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and all Linux development is
mainly happening on GitHub.

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To work with Git successfully,

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It helps if you understand
the Git workflow.

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After cloning, the developer makes changes

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to the working tree.

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All changes are made to
the local repository,

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and developers can push changes
to the remote repository.

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And if the local repository
is network accessible,

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the owner of the repository
can even pull changes from it,

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but that's pretty uncommon.

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Normally the push is developer initiated.

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Now in Git, there are
these different trees.

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The Git repository has
three trees in total

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and these trees are stored as files

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in the .git directory on
the developer workstation.

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The working directory
holds the actual files,

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the index acts as a staging area

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and the HEAD points to the
last commit that was made.

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We're working with Git,

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the git add command is used
to add files to the index.

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I'll show you all about that,

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but first I want to give you the overview.

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So git add is the first step.

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Next, you are going to commit the files

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that you have just added

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to the HEAD using git commit
followed by a commit message.

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This commit message is also
published on the Git website,

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so it's pretty important
to make a clear message

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so the users can see
what exactly has changed.

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Now, in order to connect

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to a remote repository from the client,

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you need git add origin

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and that will make the connection for you.

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And on the Git client,

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you identify this Git
remote repository next

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by using git remote add origin,

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where origin is the identifier

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for the Git repository,
it can be anything.

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Instead of origin, you will also find main

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and master for instance.

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So to complete the sequence,
you use git push origin main,

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and there you replace the name main

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with your actual branch that
you want to push changes to.

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Alright, let's try to
understand the Git procedure.

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So it all starts on the Git server

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and from the get server,

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you are going to use git clone command.

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And this get clone command

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or git pull command
comes down to the same.

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That makes that you have your files

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on what we will call the Git client.

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Now, from the Git client,

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you are going to work with your files.

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So we call it the working directory

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and that is where you are
going to add your files.

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So, in the working directory,
you apply your changes,

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and these changes need to
be added using git add.

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Now, while working with Git, your files

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and these files can be
in different states.

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You can use git status

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to figure out what the actual state is.

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So the three states are modified.

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So modified is what you get

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if the file in the
working tree is different

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from the file in the repository.

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Staged is where the
modified file was added

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to a list of changed files in the index.

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And committed is where the
modified file has been committed

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to the HEAD and is ready to be pushed.

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After committing a file
to the local repository,

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it can be pushed to the remote repository.

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Now that we know a little bit

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in general about the working of Git,

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let's further explore and let's
talk about authentication.