# Getting Started with Git

*Git is a version control system that helps you track changes in code, collaborate with others, and manage different versions of a project. This guide introduces the core concepts and basic commands to get you started with Git.*

---

## What is Version Control? 

Version control allows you to:
- Track the history of changes to files
- Revert to previous versions if something breaks
- Work on new features or fixes without affecting the main project
- Collaborate with others without overwriting each other's work

Git is a distributed [version control](https://www.atlassian.com/git/tutorials/what-is-version-control) system, meaning every user has a complete copy of the project history.

## Installing Git
```bash
sudo apt update
sudo apt install git
```

## Basic Git Workflow

1. **Initialize a repository**
- Turns a directory into a Git repository
```bash
git init
```
> **_NOTE:_** This creates a hidden `.git` subdirectory within the directory that contains necessary structures that git uses to track changes, manage histroy, and perform version control operations for the project directory. If you want to collaborate with others, or back up your code, you will need to create a remote repositroy on GitHub, or GitLab. See: "Connecting to a Remote Repository" below.
2. **Check repository status**
- Allows you to monitor changes made since your last commit
```bash
git status
```
3. **Add files to a staging area**
- Add changes to a your staging area that are ready to be included in your next commit
```bash
git add filename
git add . # Adds all files in the directory
git add -p # Sorts through changes to add one by one
```
4. **Commit changes**
- Create a permanent snapshot of your changes in your local repository
```bash
git commit -m "Describe what you changed or added"
```
5. **View commit history**
- Shows a list of commits made in reverse chronological order
```bash
git log
```

## Connecting to a Remote Repository
To collaborate with others, you'll typically push your code to a platform like GitHub, GitLab, or Bitbucket. You will need to create the repository from GitHub, or GitLab's UI. Once created, you can add your initialized local repository to the remote repository by following these steps:

### Add a remote repository
```bash
git remote add origin https://github.com/yourusername/your-repo.git
```
### Push your code
```bash
git push -u origin main
```
- The `-u` (upstream) links your local branch to a remote repository.

## Branching and Merging

### Creating a new branch
```bash
git checkout -b branch-name
```
### Switch branches
```bash
git checkout branch-name
```
### Merge a branch
```bash
git merge branch-name
```
### Delete a branch
```bash
git branch -d branch-name
```

## Cloning a Repository
To download a remote project and work on it:
```bash
git clone https://github.com/username/project.git
```

## .gitignore File
Use a `.gitignore` file to exclude files or directories from being tracked by Git.

**Example:**
```bash
*.log
.env
__pycache__/
node_modules/
```

## Undoing Changes
- Unstage a file
```bash
git reset HEAD filename
```
- Discard changes in a file
```bash
git checkout -- filename
```
- Revert a commit
```bash
git revert <commit-id>
```
- Remove a file from staging
```bash
git rm <file-name>
```

---
## Resources
- [GitHub Learning Lab](https://github.com/apps/github-learning-lab): bot lead series of practical projects to level up your GitHub skills
- [Git Branching](https://learngitbranching.js.org/?locale=en_US): a visual and interactive way to learn Git on the web
- [Git Book (free)](https://git-scm.com/book/en/v2): a free complete and indepth Git resource
- [Git Cheatsheet (GitHub)](https://education.github.com/git-cheat-sheet-education.pdf): features the most important and commonly used Git commands for easy reference.
- [Git-it](https://github.com/jlord/git-it-electron): a desktop app that teaches you how to use Git and GitHub on the command line.
- [Missing Semester of Your CS Education](https://missing.csail.mit.edu/2020/version-control/): Version Control (Git)