What Is Gitignore? Understand It in 5 Minutes

May 22, 2025

Ever discovered unwanted files cluttering your Git repository? That’s where .gitignore enters the picture.

What is gitignore? Simply put, it’s a text file that tells Git which files and directories to ignore when making commits. This powerful tool is essential for any developer working with version control systems.

When collaborating on software projects, not everything belongs in your source code management. Build outputs, dependency folders, and sensitive information should stay local. A well-configured .gitignore file keeps your repositories clean and your workflows efficient.

In this guide, you’ll learn:

How to create and configure gitignore files
Essential gitignore syntax and pattern matching
Common gitignore templates for different programming environments
Troubleshooting tips when your ignore patterns aren’t working

Whether you’re setting up your first repository or optimizing your Git workflow, mastering .gitignore will save you countless headaches and strengthen your development environment.

What Is Gitignore?

Gitignore is a file in a Git repository that specifies which files or directories should be ignored by Git. It prevents unnecessary or sensitive files, like build artifacts, logs, or environment configs, from being tracked or committed. This helps keep the repository clean and focused on relevant source code.

Getting Started with Gitignore

maxresdefault What Is Gitignore? Understand It in 5 Minutes

The .gitignore file is crucial for repository management when working with Git. It tells your version control system which files and directories to skip during commits.

Location in your project structure

The .gitignore file sits in the root of your Git repository. This is where Git looks first when determining which files to track. You’ll find it alongside other config files in your project structure.

Creating this file is simple. Just add a text file named exactly .gitignore to your local repository. No extension needed.

Some developers prefer a global gitignore setup for common system files that should never be tracked across any projects. This approach streamlines your development environment significantly.

Creating your first gitignore file

First time with Git basics? No problem. Here’s how to add a .gitignore:

Open your terminal or command prompt
Navigate to your project’s root directory
Create the file with touch .gitignore (Unix) or echo > .gitignore (Windows)
Edit the file with your preferred text editor

The gitignore location matters. Git only applies the rules to files in the same directory and subdirectories where the .gitignore resides. For complex projects, consider using nested gitignore files.

Basic Gitignore Syntax

The .gitignore syntax is straightforward but powerful. Each line specifies a pattern for files or folders that should remain untracked files in your source code management.

Simple pattern matching

Add a filename or path on each line to ignore it:

# Ignore a specific file
config.json

# Ignore all files with this extension
*.log

Plain text entries match files and folders with that exact name. The gitignore format is case-sensitive on most platforms.

Common symbols and what they mean

The .gitignore file uses several special characters for ignore patterns:

* matches zero or more characters (a gitignore wildcard)
? matches a single character
[abc] matches any character in the brackets
[0-9] matches any digit
/ is used for directory separators
** matches nested directories (e.g., logs/**/*.log ignores all .log files in the logs directory and its subdirectories)

You can use these to create complex gitignore rules that target exactly what you need to exclude from your code versioning.

Comment lines for readability

Add comments to explain your patterns. This helps team members understand your ignore files logic:

# Ignore build artifacts
build/
dist/

# Ignore editor config files
.vscode/

Comments make your .gitignore more maintainable. This is essential for team collaboration and follows Git best practices.

Common Gitignore Patterns

Let’s explore the most useful patterns for effective repository setup.

Ignoring File Types

Most projects generate files that shouldn’t be tracked or shared. Exclude files based on patterns.

Using wildcards for extensions (.log, .tmp)

The asterisk wildcard is perfect for ignoring all files of a certain type:

# Ignore all log files
*.log

# Ignore temporary files
*.tmp
*.temp

This pattern is common for gitignore examples dealing with compiled files and other outputs from your build process.

When working with sensitive information, always ignore:

# Credentials should never be committed
*.pem
*.key
*credentials*
.env

The gitignore credentials pattern protects your secrets from accidental exposure in your source control.

Ignoring specific files by name

Sometimes you need to ignore particular files:

# Project configuration
config.local.js
secretkey.txt

This approach works well for environment variables and other configuration files that might differ between developers.

Ignoring Directories

Folders often contain generated content or dependencies that shouldn’t be tracked.

Syntax for entire folders

To ignore a complete directory:

# Ignore node_modules directory
node_modules/

# Ignore build outputs
dist/
build/

The trailing slash is optional but recommended as it clarifies you’re ignoring a directory. This pattern is fundamental for gitignore node modules and other dependency directories.

For cache files and log files, use:

# Ignore cache directories
.cache/
__pycache__/

# Ignore logs
logs/

This keeps your local repository clean of files that would bloat your source code unnecessarily.

Ignoring content but keeping folder structure

Sometimes you want the directory but not its contents:

# Keep the logs directory but ignore its contents
logs/*
!logs/.gitkeep

This technique preserves the folder structure while ignoring the files inside, using the gitignore all files except pattern combined with an exception rule.

Exceptions to Ignore Rules

You can create exceptions to your ignore patterns using the exclamation mark.

Using the exclamation mark (!)

The ! symbol negates a pattern, allowing you to make exceptions:

# Ignore all .md files
*.md

# But keep README.md
!README.md

This approach is often used for gitignore vs .git/info/exclude decisions when you need finer control over inclusion and exclusion.

When to make exceptions

Exceptions are useful when:

You need to keep specific important files while ignoring others of the same type
You want to ignore everything in a directory except certain files
You’re working with templates or example files that should be committed

When editing gitignore, remember that order matters in your patterns. The last matching pattern determines whether a file is ignored.

By understanding these fundamental concepts, developers can maintain cleaner repositories and streamline their Git workflow considerably.

Ready-Made Gitignore Templates

Why reinvent the wheel? The Git community has developed extensive template collections for almost every development environment. These templates save time.

GitHub’s Collection of Templates

GitHub maintains a comprehensive repository of .gitignore templates. They cover virtually all programming languages and frameworks used in modern software development.

Finding language-specific templates

Finding the right template is simple:

Visit github.com/github/gitignore
Browse alphabetically or search for your language
View the raw file contents
Copy the template

These templates are maintained by the open source community and regularly updated. They follow Git best practices and address common needs for each language or platform.

Popular templates include gitignore languages like Python, JavaScript, Java, and C++. Each considers the unique build artifacts and tooling of that ecosystem.

The gitignore syntax in these templates demonstrates professional patterns. Study them to improve your own gitignore rules.

How to use them in your project

Using a template requires just a few steps:

Download or copy the template content
Create a .gitignore file in your local repository
Paste the template contents
Customize as needed for your specific project

You can also use gitignore generators that combine multiple templates based on your tech stack. These tools assemble comprehensive .gitignore files tailored to complex projects.

The git init command can automatically apply templates with the --template flag. This streamlines your repository setup.

Common Templates for Popular Environments

Different ecosystems have different needs. Understanding environment-specific patterns improves your repository management.

Node.js, Python, Java templates

Node.js projects typically ignore:

# Dependencies
node_modules/
jspm_packages/

# Coverage directories
coverage/

# Build outputs
dist/
build/

Python developers commonly exclude:

# Byte-compiled files
__pycache__/
*.py[cod]
*$py.class

# Distribution/packaging
dist/
build/
*.egg-info/

# Virtual environments
venv/
env/
ENV/

Java projects usually ignore:

# Compiled class files
*.class

# Package files
*.jar
*.war
*.ear

# Build directories
bin/
build/
target/

These templates account for the unique package manager systems and compiled files in each environment.

IDE-specific ignore patterns (VS Code, JetBrains)

Different text editors and IDEs create their own metadata. Keep these out of your source control with specific patterns:

VS Code:

.vscode/*
!.vscode/settings.json
!.vscode/tasks.json
!.vscode/launch.json
!.vscode/extensions.json

JetBrains (IntelliJ, WebStorm, PyCharm):

# Covers all JetBrains IDEs
.idea/
*.iml
*.iws
out/

These patterns prevent system files from cluttering your repository. They’re often included in programming language templates but can be added separately.

Practical Gitignore Examples

Theory helps. Practical examples clarify. Let’s explore real-world patterns.

For Web Development Projects

Front-end and back-end web development generates many files that should be excluded.

Node modules and dependency folders

The node_modules directory is the classic example:

# Dependencies
node_modules/
bower_components/

# Environment variables
.env
.env.local
.env.development
.env.test
.env.production

The sheer size of Node modules makes them impractical to track in Git. Their inclusion would bloat repositories and slow Git commands significantly.

Your package.json and lock files track dependencies, making the actual modules redundant in source code management.

Build outputs and compiled files

Modern web projects separate source from output:

# Build directories
dist/
build/
out/

# Compiled CSS from preprocessors
*.css.map
*.sass.cache

# Minified files
*.min.js
*.min.css

These build artifacts are generated from source files. Including them creates merge conflicts and version control confusion.

For React, Vue, or Angular projects, accommodate framework-specific patterns:

# React/Next.js specific
.next/
out/

# Vue specific
.nuxt/
dist/

# Angular
.angular/cache

For Data Science and Machine Learning

Data science projects have unique requirements due to large files and environment specifics.

Large datasets and model files

Data and models often exceed Git’s practical size limits:

# Datasets
data/
*.csv
*.json
*.xlsx
!sample_data.csv

# Models
models/
*.h5
*.pkl
*.pt
*.model

The exception rule (!sample_data.csv) allows including a small sample dataset while excluding the full data. This follows the gitignore all files except pattern.

Use Git LFS (Large File Storage) for critical large files that must be tracked. Standard Git isn’t designed for binary storage.

Environment-specific settings

Data science environments vary widely:

# Jupyter
.ipynb_checkpoints/
*/.ipynb_checkpoints/*

# Virtual environments
venv/
env/
.conda/

# R specific
.Rproj.user/
.Rhistory
.Rdata

These patterns accommodate tools like Jupyter notebooks, R studio, and common Python environment managers.

For Mobile App Development

Mobile app development generates platform-specific artifacts that shouldn’t be tracked.

Platform-specific build files

For iOS development:

# Xcode
build/
*.pbxuser
*.mode1v3
*.mode2v3
*.perspectivev3
xcuserdata/
*.xccheckout
*.xcscmblueprint
*.xcworkspace

# Obj-C/Swift specific
*.hmap
*.ipa
*.dSYM.zip
*.dSYM

For Android development:

# Gradle files
.gradle/
build/

# Local configuration
local.properties

# Android Studio
*.iml
.idea/
captures/
.navigation/
.externalNativeBuild/

These patterns address the specific IDE files and build systems used in mobile development.

Dependency management ignores

Mobile dependencies should also be excluded:

# iOS (CocoaPods)
Pods/

# Android
google-services.json

Remember that the order of gitignore rules matters. More specific rules should come after general ones. This ensures your exception patterns work as expected.

By leveraging these templates and examples, your Git workflow will improve significantly. You’ll keep repositories clean and focus on what matters: your source code.

Troubleshooting Gitignore Issues

Even experienced developers run into gitignore problems. Let’s solve common issues.

When Files Aren’t Being Ignored

The most frequent problem? Files specified in .gitignore still appear in git status. Frustrating but fixable.

Cached files in Git

Git won’t ignore files that are already tracked. This trips up many developers.

The issue occurs because Git has already indexed these files in its local repository. Your new gitignore rules only affect untracked files or files you’ve just added to the repository.

If you’ve recently added patterns to your .gitignore file but committed changes previously, Git continues tracking those files. The solution is simple.

Using git rm –cached

Remove already-tracked files from the Git index without deleting them from your working directory:

# Remove a single file from tracking
git rm --cached filename.ext

# Remove an entire directory
git rm --cached -r directory/

After running this command, the files remain in your project structure but Git stops tracking them. Commit these changes to ensure everyone on your team gets the updated tracking rules.

This approach is particularly useful for removing sensitive information like API keys or credentials that were accidentally committed.

Common scenarios where you’ll need this:

Adding credentials to .gitignore after they were accidentally committed
Updating project to ignore build artifacts that were previously tracked
Applying a new .gitignore file to an existing repository

Fixing Common Mistakes

Small mistakes in your .gitignore file can lead to unexpected behavior.

Order of rules matters

The order of patterns in your .gitignore file is significant. Git processes the file from top to bottom, with later rules taking precedence.

Incorrect:

# This won't work as expected
!important.log
*.log

In this example, important.log will still be ignored because the *.log pattern comes last.

Correct:

# This works correctly
*.log
!important.log

This pattern ignores all log files except for important.log. Understanding this ordering is essential for gitignore syntax.

Path issues and folder structure problems

Path specifications in .gitignore can be tricky:

Patterns without slashes match files and directories in any directory
Patterns ending with a slash match only directories
Patterns starting with a slash match from the repository root

Common path mistakes:

Incorrect:

# This only ignores node_modules in the root
/node_modules

This pattern ignores the node_modules directory only in the root of your project, not in subdirectories.

Correct:

# This ignores node_modules anywhere in the repository
node_modules/

Your directory patterns should align with your project structure. Be specific with paths when needed.

# Ignore logs directory at the root
/logs/

# Ignore logs directories anywhere
logs/

# Ignore specific nested directory
src/temp/build/

When dealing with nested gitignore files, remember that each .gitignore applies to its directory and all subdirectories.

Best Practices for Using Gitignore

Effective .gitignore management improves your Git workflow and team collaboration.

What Should Always Be Ignored

Some files should never be committed to source control. Add these to your .gitignore by default.

Sensitive credentials and API keys

Never commit secrets:

# Environment files with secrets
.env
.env.local
*.env.development

# Key files
*.pem
*.key
id_rsa
id_dsa

# Configuration with secrets
config.json
credentials.yml

The risk of exposing sensitive information in public repositories is substantial. Even in private repositories, limiting access to credentials follows good security practices.

Use environment variables or secret management tools instead of hardcoding secrets in your source code.

Large binary files and datasets

Git isn’t designed for large files:

# Large media files
*.mp4
*.mov
*.psd
*.ai

# Data files
*.csv
*.xlsx
*.db
*.sqlite

# Archives
*.zip
*.tar.gz
*.rar

These large binaries bloat your repository and slow down clones and fetches. For necessary large files, consider using Git LFS (Large File Storage) or a dedicated data storage solution.

System and IDE files

Operating system and tooling files don’t belong in repositories:

# macOS
.DS_Store
.AppleDouble
._*

# Windows
Thumbs.db
Desktop.ini

# Linux
*~
.directory

# IDE files
.idea/
.vscode/
*.sublime-project
*.sublime-workspace

These system files vary between developers and cause unnecessary merge conflicts. They provide no value in source code management.

Team Collaboration with Gitignore

Consistent .gitignore practices strengthen team workflows.

Everyone on your team should use the same ignore patterns:

Commit your .gitignore file to the repository
Document any unusual patterns with comments
Update the file when project dependencies change
Consider using gitignore templates as a starting point

For teams using multiple programming languages or frameworks, combine relevant templates into a comprehensive .gitignore file.

Global vs. local gitignore settings

Git supports two levels of ignore patterns:

Repository-specific: The .gitignore file in your project
Global: Your personal ignore file that applies to all repositories

Configure a global gitignore for your common tools and OS:

# Set up a global gitignore file
git config --global core.excludesfile ~/.gitignore_global

Then create ~/.gitignore_global with your personal patterns:

# Editor files
.vscode/
.idea/

# OS files
.DS_Store
Thumbs.db

# Personal notes
TODO.md
NOTES.md

Keep repository-specific patterns in the project’s .gitignore and personal preferences in your global file. This separation respects team standards while accommodating individual workflows.

When editing gitignore, consider:

What belongs in the repo-specific file vs. global file
Which patterns are essential for all team members
How to structure the file for readability

Advanced tip: For temporary ignores that shouldn’t be committed, use .git/info/exclude. This file works like .gitignore but isn’t shared with other developers, making it perfect for personal, temporary exclusions.

By following these practices, you’ll avoid common gitignore pitfalls and create a cleaner, more efficient development environment for yourself and your team.

FAQ on What Is Gitignore

What exactly is a .gitignore file?

A .gitignore file is a plain text file that instructs Git which files or directories to ignore in a project. It prevents specified untracked files from being added to the version control system, keeping your repository clean and focused on essential source code.

How do I create a .gitignore file?

Create a text file named exactly .gitignore in your repository root. Use any text editor to add patterns of files to ignore. For quick setup, run touch .gitignore in your terminal or use your IDE’s file creation tool.

What are the most common patterns used in gitignore?

Common gitignore patterns include:

*.log (all log files)
node_modules/ (dependency folders)
*.tmp (temporary files)
.env (credentials)
build/ or dist/ (compiled outputs)
.DS_Store (system files)
.idea/ or .vscode/ (IDE settings)

Can I have multiple .gitignore files in one repository?

Yes. You can place nested gitignore files in different directories of your project structure. Each .gitignore applies to its directory and all subdirectories, allowing for more granular ignore rules in complex projects.

Why are my files still being tracked despite being in .gitignore?

Files already tracked by Git won’t be affected by new gitignore rules. Use git rm --cached <file> to stop tracking while keeping the file in your local repository. This is common when adding gitignore to existing projects.

Where can I find templates for different programming languages?

Find gitignore templates on GitHub’s official collection: github.com/github/gitignore. Many version control platforms and IDEs offer built-in templates. Gitignore generators like gitignore.io combine templates for your specific development environment.

How do I ignore all files except certain ones?

To implement a gitignore all files except pattern:

# Ignore everything
*
# But not these files
!.gitignore
!important.js
!src/

This ignores everything then creates exceptions for specific files and directories.

Can I use comments in my .gitignore file?

Yes. Gitignore comments start with #. Use them to organize your file and explain complex patterns to team members. Comments improve readability and help with team collaboration on source control management.

How do I set up a global gitignore?

Create a global gitignore with:

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

Then edit ~/.gitignore_global to add patterns. This affects all repositories on your machine without modifying project-specific files.

What’s the difference between .gitignore and .git/info/exclude?

Both use the same gitignore syntax, but .gitignore is committed and shared with all repository users, while .git/info/exclude is local and not shared. Use .gitignore for project-wide ignores and .git/info/exclude for personal preferences.

Conclusion

Understanding what is gitignore transforms how you manage your Git projects. This simple text file serves as the gatekeeper for your repository, ensuring only essential source code gets committed. By implementing proper ignore patterns, you maintain cleaner history and more efficient workflows.

The power of .gitignore extends beyond basic file exclusion. It becomes a critical component of your development environment when you:

Protect sensitive information like API keys and credentials
Exclude build artifacts and compiled files that can be regenerated
Skip hidden files specific to your operating system or tools
Maintain proper ignore patterns for team standardization

Mastering gitignore format might seem trivial, but it significantly impacts your project management and code versioning processes. Whether you use language-specific templates or craft custom rules, proper file exclusion streamlines collaboration.

Remember to revisit your .gitignore as projects evolve. As new dependencies or build outputs emerge, update your patterns accordingly. This ongoing maintenance is a hallmark of professional repository management and Git best practices.

Author
Recent Posts

Bogdan Sandu

Bogdan is a seasoned web designer and tech strategist, with a keen eye on emerging industry trends.

With over a decade in the tech field, Bogdan blends technical expertise with insights on business innovation in technology.

A regular contributor to TMS Outsource's blog, where you'll find sharp analyses on software development, tech business strategies, and global tech dynamics.