Big

The Basics of Git

Who am I?

Craig Reeder

Cloud Engineer @
Uturn Data Solutions

I love tooling

I really love tooling

Git is one of my favorite tools

What is Git?

Distributed Version Control Software

Created by Linus Torvalds in 2005
(To manage Linux source code) Though it's been largely developed by others since

Quick Note: GitHub

GitHub is just a hosted platform for Git
And some other cool stuff

Git is to GitHub as Burgers are to BurgerKing

What does git do?

Tracks changes

Keeps history

Enables collaboration

Everyone has a full copy This has proved useful for recovery purposes

Why use git?

Ever done this?

project/
    config-4.3.20
    config-1.5.21
    config-7.8.21
    config-live

Never do that again!

Git has history

All changes
(since the beginning of time)

Easily reversable

Who broke it?

$ git log

Author: Travis Langhals <tlanghals@example.com>
Date:   Fri Sep 3 12:13:57 2021 -0400

Remove the Fizz from the Buzz, it's not needed

(spoiler alert: it was needed)

Great! How do I use it?

Creating a new repository:

$ git init

This creates a new repository in the current directory

Time to make some changes

To save your changes, you need to tell git you want to include them This feels silly, but this means that you can select which changes to actually save, or break them into smaller chunks

Stage your changes:

$ git add foo.html bar.js

Finalize your changes into the git history:

$ git commit

This will prompt you in an editor for a message.
It is possible to change which editor it uses. https://bit.ly/3hdSdNq

Don't have commitment issues

Commit early and often

It's not that easy! I got lost!

See the current state of things:

$ git status

It'll show something like this:

On branch main
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
  modified:   index.html
  modified:   themes/dark.css

Working locally cheat sheet:

$ git init # once, for a new repo

# make changes to files
$ git add file.txt
$ git commit

Now let's work as a team

Getting an existing repository:

$ git clone git@github.com:torvalds/linux.git

Quick Note: Authentication

This uses ssh to clone:

$ git clone git@github.com:torvalds/linux.git

This uses https to clone:

$ git clone https://github.com/torvalds/linux.git

Select it here on GitHub

SSH relies on the key you already created

HTTPS will prompt you for credentials every time
(Unless you set up a credential manager)

SSH works better with most automation

Back to the commands

Someone made a change to a repository you cloned
Oh no! What do I do? 😢

Pull changes from remote:

$ git pull

Now you're up to date!

Stage your changes:

$ git add foo.html bar.js

Finalize your changes into the git history:

$ git commit

Commiting is local only

To share your changes:

$ git push

The first time you do this in a branch, you'll get an error message with an additional flag. Follow the instructions.

One more important concept

Git is a tree

(sometimes displayed sideways)

Trees have branches

Git has branches!

(and a trunk)

You'll hear tree terminology used a lot around git

The default branch is usually main
Sometimes it's called "master" It'll be master if you init on your machine. This is a simple configuration option.

Create a new branch:

$ git branch widget-fix

Change to a branch:

$ git checkout widget-fix

Merging is the act of combining branches

We're not going to cover manually merging

With GitHub, you can create a pull request Also with most hosted git repos

This is a request to merge your branch into another
Typically main

Best practice with a pull request is to have someone else review your code

GitHub has useful commenting and approval tools

GitHub Flow:

Steps:

Step 1) Make a feature branch
Step 2) Make your changes
Step 3) Commit your changes
Step 4) Push your changes
Step 5) Make a Pull Request
Step 6) Fix any feedback from review (repeat 2-4)
Step 7) Merge the PR

Step 1) Make a feature branch

$ git branch widget-fix
$ git checkout widget-fix

Step 2) Make your changes

Step 3) Commit your changes

$ git add fixed-files.txt
$ git commit

Step 4) Push your changes

$ git push

Step 5) Make a Pull Request

Step 6) Fix any feedback from reviews
And repeat steps 2-4 (make changes, commit, push)

Step 7) Finally, merge the PR

The final reviewer will likely do this step

Some final thoughts

VSCode is git aware It will show you what has changed since your last commit

All of the git commands can be done in VSCode with context menus
Look for the "source control" icon on the left While I prefer the commandline, this is an easy way to get started.

.gitignore is a special file that tells git which files to ignore.

Those files won't ever be staged or commited

Now for some hands on!

Try these commands (or do the following in VSCode):

$ git init # once, for a new repo
$ git add file.txt # create file.txt first
$ git commit
$ git status
$ git branch widget-fix
$ git checkout widget-fix

$ git clone <url> # new repo! get this from github
$ git branch your-username
$ git checkout your-username
$ git add file.txt # create file.txt first
$ git commit
$ git push # follow the instructions

fin.