How to add a .gitignore file to your Git repository

Have you ever accidentally committed sensitive information like passwords, configs, or large files to your Git repository? If the answer is yes, then you need to learn how to handle the .gitignore file. In this article, I'll walk you through how to create a .gitignore file in a Git repository and optimize it for different tech stacks.

The .gitignore file is a special file in Git that lets you specify which files or folders should be ignored by Git when committing to your repository. In other words, anything listed in this file will be excluded from version control.

To create a .gitignore file in a Git repository, run this command in your project root:

touch .gitignore

Then, open the file in your favorite code editor to add the rules.

# Ignore dependency files
node_modules/

# Ignore environment variables
.env

# Ignore logs
*.log

The rules in .gitignore are based on simple patterns:

Besides the local .gitignore, Git also lets you use a global .gitignore file to apply rules across all your projects:

git config --global core.excludesfile ~/.gitignore_global

You can place in this file common rules used in every project, like:

# Mac OS
.DS_Store

# Temporary files
*.tmp

Here are ready-to-copy examples based on the tech stack you're using:

/vendor/
/node_modules/
.env
Homestead.json
Homestead.yaml
.phpunit.result.cache

node_modules/
dist/
.env
npm-debug.log*
yarn-debug.log*
yarn-error.log*

__pycache__/
*.py[cod]
.env
*.sqlite3

You can find a full collection of templates here: github/gitignore

• Use templates: Don’t reinvent the wheel. Use proven templates like the ones on GitHub.
• Check files before committing: Always check which files you're about to commit using git status.
• Be careful with sensitive data: Files like .env should never go into the repo.
• Keep it updated: Revisit your .gitignore regularly and adapt it as your project grows.

• Environment variables (.env, .env.local)
• Dependencies (node_modules, vendor)
• Local databases (*.sqlite3, *.db)
• Logs (*.log)

# Environment variables
.env
.env.local

# Dependencies
node_modules/
vendor/

# Local databases
*.sqlite3
*.db

# Logs
*.log

1. What happens if I add a file to .gitignore after it’s already committed? Git will still track the file unless you remove it with:

git rm --cached filename

Then, it will be ignored in future commits.

2. Can I ignore a folder but keep a file inside it? Yes. For example:

folder/*
!folder/keepme.txt

This ignores everything in folder except keepme.txt.

3. Is .gitignore case-sensitive? Yes, on case-sensitive file systems like Linux. On Windows or macOS, behavior may differ.

4. Where should I place the .gitignore file? At the root of your repository. You can also have nested .gitignore files inside subdirectories if needed.

5. Does .gitignore affect files already in the remote repository? No. It only applies to local changes. You must manually remove files from the repo if you want them gone.

A well-configured .gitignore file is key to keeping your Git project secure, organized, and clean. Creating a .gitignore file in a Git repository using these tips will help you avoid common mistakes and work more efficiently.

Want to go deeper? Here's GitHub's official documentation on ignored files and advanced patterns.

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Happy coding 😎