1.1-what_is_git.qmd

---
title: "Intro to `git`"
subtitle: "Block 1.1: What is git?"
---

::: attribution
Background: https://unsplash.com/photos/842ofHC6MaI
:::

## What is git?

- Version Control System (VCS)
  - Looks at the changes in your files
  - Records all changes over time to give you a full history
  - Similar to "track changes" in Microsoft Word / LibreOffice

::: {.fragment}

![Git only looks at and tracks the *changes* in a file](images/carpentries/play-changes.svg)

:::

## What is git? *Strengths* & Weaknesses

- Strengths 💪
  - Very hard to lose files with git
  - Great for collaboration
  - Fast (like, really fast)
  - History allows you to go back and understand changes or revert when there are problems
  - Reproducibility

## What is git? Strengths & *Weaknesses*

- Weaknesses 😢
  - Can be a bit complicated to use (esp. at first)
  - History takes up file space (but only little)
  - Struggles with binary (i.e. non-text) files
  - Struggles with large files
    - Not good for storing data!
  - You do need to *explicitly* use it i.e. it doesn't just work in the background

## CLI vs. GUI?!

Git can be used via both a CLI and GUI.

:::: {.columns}

::: {.column width="50%"}
*Command Line Interface (CLI)*

- Also Console or Terminal
- Only text
- You type your command, press enter and receive back text
- *Very* flexible, but a bit unintuitive
:::

::: {.column width="50%"}
*Graphical User Interface (GUI)*

- Most applications nowadays
- Often asier to use
- Typically mainly controlled via your Mouse
- Buttons and other clickable elements
:::

::::

## CLI vs. GUI?!

:::: {.columns}

::: {.column width="50%"}
![An example of using git in a command line interface (CLI)](images/screenshots/terminal-empty.png)
:::

::: {.column width="50%"}
![An example of using git in SourceTree, a graphical user interface (GUI)](images/screenshots/sourcetree-test.png)
:::

::::

## CLI vs. GUI: `git`

- `git` itself is a CLI program
- But, many GUIs are available
  - [Sourcetree](https://www.sourcetreeapp.com/)
  - [Visual Studio Code](https://code.visualstudio.com/)*
  - [Rstudio](https://posit.co/download/rstudio-desktop/)*
  - [Github Desktop](https://github.com/apps/desktop)
  - ... (full list: <https://git-scm.com/downloads/guis>)

::: {.fragment}

*: These programs have a different main purpose, but also offer the option of using git via their GUI.

:::

## Using the `git` CLI

- We will first use git via its CLI (i.e. in the Terminal).
  - On windows, open Git Bash (start menu -> Git Bash).
  - On MacOS, open the Terminal app.
  - On Linux, open your distribution’s (or any other) terminal emulator.
- Let's do this together now!

## Using the `git` cheatsheet to follow along

- There are many existing cheatsheets out there with the most important git commands
- In this course we will be using the one from [GitHub Education](resources/git-cheat-sheet-education.pdf) to help you navigate the course

## Let's Set Things Up: `git config` ⚙️

Run the following commands in your terminal to correctly configure git on your computer.

```bash
# Add your name
git config --global user.name "Your Name"

# Add your email address
git config --global user.email "your.email@kit.edu"

# Use modern main branch name
git config --global init.defaultbranch main
```

## Let's Set Things Up: `git config` ⚙️

For Linux/Mac:

```bash
git config --global core.autocrlf input
```

For Windows:

```bash
git config --global core.autocrlf true
```

Why? Windows saves linebreaks (enter) differently then Linux/Mac does 🤷‍♂️

# Getting started with git (for real) {background-color="black" background-opacity="0.7" background-image="images/backgrounds/rolling-up-sleeves.gif"}

::: attribution
Background: Warnerbros, via [Digital Spy](https://www.digitalspy.com/movies/a823040/harry-potters-jason-isaacs-says-co-star-alan-rickman-stole-from-gringotts-bank/)
:::

## See what's happening: `git status`

A project in git is called a **repository** (or **repo** for short) and it always corresponds to a directory on your machine.

To see the current status of a git repository you can run the `status` command.

```bash
git status
```

## See what's happening: `git status`

```bash
git status
# fatal: not a git repository (or any of the parent directories): .git
```

We get an error here, because you first need to *initialize* a git repository.

## Initializing a repository: `git init`

Before we can use git in a project we first have to initialize it in the directory of the project. This is done via the `init` command.

```bash
git init
# Initialized empty Git repository in /Users/jan/Dev/temp/test/.git/

git status
# On branch main
# No commits yet
# nothing to commit (create/copy files and use "git add" to track)
```

With `git init` we turn the *directory* into a *repository*.

## Practical: init {background-color="black"}

1. Identify the filepath of the **directory** you created earlier.
2. Open the Terminal (or Git Bash on Windows) in VS Code
3. Use `git init` to initialize a new repository there
4. Keep VS Code open in this directory for later

## Downloading a repository: `git clone`

Alternatively, we can download a repository from the internet using the `clone` command. This will create a new repository on our machine and fill it with the remote repository's contents.

```bash
git clone https://github.com/open-teaching/git-murder-mystery.git
```

## *End of Section* 🎉 {background-color="black"}

:::{.r-fit-text}
Any Questions?
:::

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