2.1-gitignore.qmd

---
title: "Intro to `git`"
subtitle: "Block 2.1: Ignoring things: `.gitignore`"
---

## Ignoring files via `.gitignore` 🙈

- By default, git will track *all* the files in your repository.
- If you want it to ignore certain files or filetypes, you have to tell it so explicitly.
- You can do this by using a file called `.gitignore`
  - Every file will be compared against the list in `.gitignore` and if it matches, git will ignore the file
- The `.gitignore` file *itself* is tracked just like any other file

## `.gitignore`: classic examples

Ignore every file called myfile.pdf

```bash
myfile.pdf
```

Ignore the file called myfile.pdf in the folder reports at the root of your *repository*

```bash
/reports/myfile.pdf
```

Ignore all PDF files

```bash
*.pdf
```

:::{.callout-tip}
The .gitignore uses the same kind of pattern matching as `git add` (or other git commands)
:::

## `.gitignore`: global vs. local 🫥

- There can be multiple different `.gitignore` files at different levels
- There's one *global* `.gitignore`, that will work across your whole computer
- There are local gitignore files within your repositories
  - You can even have a gitignore file in a directory within your repository and it will apply only within that directory
  - You can find a list of very useful templates for local`.gitignore` files at <https://github.com/github/gitignore>.
  - A classic example for files to ignore globally are `.DS_Store` files on macOS.

## Once it's in, it's too late

Once a file is tracked by `git`, adding it to the `.gitignore` will not do anything.

- You will first have to remove it from git
- **Option 1:** Delete the file and commit the deletion
- **Option 2:** Remove file from index only (and commit)
  - `git rm --cached <file>`
  - ⚠️ Warning: This will delete the file for anyone else working with the repository!

## Practical: Ignoring Files {background-color="black"}

1. Go back to your VSCode Terminal in `git-exercise`
2. Google for a git cheatsheet (it should be a PDF file)
3. Copy the PDF into your `git-exercise` directory
4. Create a new .gitignore file to ignore only this cheatsheet
5. Commit the .gitignore file

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

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

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