Git

Git is a distributed version control system that helps you track changes to your code and collaborate with others.

Installation

Windows

1. Download Git from git-scm.com
2. Run the installer with default options
3. Verify installation: git --version

macOS

1. Install with Homebrew: brew install git
2. Or download from git-scm.com
3. Verify installation: git --version

Linux

# Debian/Ubuntu
sudo apt update
sudo apt install git

# Fedora
sudo dnf install git

# Verify
git --version

Initial Configuration

Set up your identity:

git config --global user.name "Your Name"
git config --global user.email "your.email@example.com"

Basic Git Commands

Creating Repositories

# Initialize a new repository
git init

# Clone an existing repository
git clone https://github.com/username/repository.git

Basic Workflow

# Check status
git status

# Add files to staging
git add filename.java    # Single file
git add .                # All files

# Commit changes
git commit -m "Descriptive message about changes"

# View commit history
git log

Working with Branches

# Create a new branch
git branch feature-branch

# Switch to a branch
git checkout feature-branch
# OR
git switch feature-branch

# Create and switch in one command
git checkout -b new-feature

# List all branches
git branch

# Merge a branch into current branch
git merge feature-branch

Remote Repositories

# Add a remote
git remote add origin https://github.com/username/repository.git

# Push changes to remote
git push origin main

# Pull changes from remote
git pull origin main

# Fetch changes without merging
git fetch origin

.gitignore

Create a .gitignore file to exclude build files and IDE configurations:

.gitignore

# Compiled class files
*.class

# Log files
*.log

# BlueJ files
*.ctxt

# Mobile Tools for Java (J2ME)
.mtj.tmp/

# Package Files
*.jar
*.war
*.nar
*.ear
*.zip
*.tar.gz
*.rar

# Virtual machine crash logs
hs_err_pid*
replay_pid*

# IDE specific files
.idea/
.vscode/
*.iml
*.iws
.classpath
.project
.settings/

# Build directories
target/
build/
out/
bin/

Workflow

1. Create a feature branch for new work:

   git checkout -b feat/user-authentication

2. Write and test your code locally

3. Commit changes with descriptive messages:

   git add src/main/java/com/example/UserAuth.java
   git commit -m "Implement user authentication with password hashing"

4. Push changes to remote repository:

   git push origin feat/user-authentication

5. Create a pull request (on GitHub/GitLab/etc.)

6. Review and merge after approval

Best Practices

• Commit early and often
• Write meaningful commit messages
• Use branches for features and fixes
• Pull changes frequently to avoid merge conflicts
• Review changes before committing
• Don’t commit generated files or credentials