How to configure Git username

# 1. Set global username (recommended for most users)
git config --global user.name "Your Full Name"

# Example configurations
git config --global user.name "John Doe"
git config --global user.name "Jane Smith"
git config --global user.name "Alex Johnson"

# 2. Set username for current repository only
git config user.name "Your Work Name"

# Example: Different identity for work repository
git config user.name "John Doe (CoreUI Team)"

# 3. View current username configuration
git config user.name                    # Repository-specific or global
git config --global user.name           # Global only
git config --local user.name            # Repository-specific only

# 4. View all Git configuration
git config --list
git config --list --global              # Global config only
git config --list --local               # Repository config only

# 5. Remove username configuration
git config --global --unset user.name   # Remove global username
git config --unset user.name            # Remove repository username

# 6. Configure username with email (common workflow)
git config --global user.name "John Doe"
git config --global user.email "[email protected]"

# 7. Verify configuration
git config --get user.name
git config --get user.email

# 8. Show where configuration is stored
git config --list --show-origin

# 9. Edit configuration file directly
git config --global --edit              # Opens global config in editor
git config --edit                       # Opens repository config in editor

# 10. Set configuration with special characters
git config --global user.name "José García"
git config --global user.name "李小明"
git config --global user.name "Müller, Hans"

# 11. Multiple identities for different contexts
# Work identity
git config --global user.name "John Doe"
git config --global user.email "[email protected]"

# Then for personal projects, use repository-specific config
cd ~/personal-project
git config user.name "Johnny"
git config user.email "[email protected]"

# 12. Conditional configuration (Git 2.13+)
# Create different configs for different directories
git config --global includeIf."gitdir:~/work/".path ~/.gitconfig-work
git config --global includeIf."gitdir:~/personal/".path ~/.gitconfig-personal

# ~/.gitconfig-work
cat > ~/.gitconfig-work << 'EOF'
[user]
    name = John Doe
    email = [email protected]
    signingkey = WORK_GPG_KEY_ID
EOF

# ~/.gitconfig-personal
cat > ~/.gitconfig-personal << 'EOF'
[user]
    name = Johnny
    email = [email protected]
    signingkey = PERSONAL_GPG_KEY_ID
EOF

# Advanced username configuration scenarios

# 13. Set username during repository initialization
git init
git config user.name "Project Maintainer"
git config user.email "[email protected]"

# 14. Clone repository and immediately set username
git clone https://github.com/user/repo.git
cd repo
git config user.name "Your Name"
git config user.email "[email protected]"

# 15. Batch configuration for multiple repositories
# Script to configure multiple repositories
for repo in ~/projects/*/; do
    if [ -d "$repo/.git" ]; then
        echo "Configuring $repo"
        cd "$repo"
        git config user.name "Your Name"
        git config user.email "[email protected]"
    fi
done

# 16. Verify commit authorship
git log --oneline --format="%h %an <%ae> %s"

# Check specific commit authorship
git show --format="%an <%ae>" --no-patch HEAD

# 17. Fix commit authorship retroactively
# Change author of last commit
git commit --amend --author="Correct Name <[email protected]>"

# Change author of multiple commits (use with caution)
git rebase -i HEAD~3  # Interactive rebase for last 3 commits
# Then for each commit to change:
git commit --amend --author="Correct Name <[email protected]>"
git rebase --continue

# 18. Configure username with organization standards
# Example: Company naming convention
git config --global user.name "Doe, John (Engineering)"
git config --global user.email "[email protected]"

# Example: Open source contribution
git config --global user.name "John Doe"
git config --global user.email "[email protected]"

# 19. Troubleshooting username issues
# Check if username is properly set
if [ -z "$(git config user.name)" ]; then
    echo "No username configured!"
    echo "Run: git config --global user.name 'Your Name'"
else
    echo "Username: $(git config user.name)"
fi

# Check configuration precedence
echo "Global username: $(git config --global user.name 2>/dev/null || echo 'Not set')"
echo "Local username: $(git config --local user.name 2>/dev/null || echo 'Not set')"
echo "Effective username: $(git config user.name 2>/dev/null || echo 'Not set')"

# 20. Best practices validation
# Check for common issues
if git config user.name | grep -q "Your Name"; then
    echo "Warning: Using placeholder name 'Your Name'"
fi

if git config user.name | grep -q "^[a-z]"; then
    echo "Note: Username starts with lowercase, consider proper case"
fi

length=$(git config user.name | wc -c)
if [ $length -lt 3 ]; then
    echo "Warning: Username seems too short"
fi

# Integration with development workflow

# 21. Automated configuration script
cat > setup-git-identity.sh << 'EOF'
#!/bin/bash

read -p "Enter your full name: " fullname
read -p "Enter your email: " email

git config --global user.name "$fullname"
git config --global user.email "$email"

echo "Git identity configured:"
echo "Name: $(git config --global user.name)"
echo "Email: $(git config --global user.email)"

# Test with a dummy commit
mkdir -p /tmp/git-test
cd /tmp/git-test
git init
echo "# Test" > README.md
git add README.md
git commit -m "Test commit to verify identity"
git log --oneline --format="%an <%ae>"
cd - > /dev/null
rm -rf /tmp/git-test
EOF

chmod +x setup-git-identity.sh
./setup-git-identity.sh

# 22. Corporate environment setup
# Template for enterprise Git configuration
cat > corporate-git-setup.sh << 'EOF'
#!/bin/bash

# Corporate Git configuration
git config --global user.name "$(id -F)"  # Use full name from system
git config --global user.email "$(whoami)@company.com"
git config --global core.autocrlf true   # Windows compatibility
git config --global pull.rebase false    # Use merge instead of rebase
git config --global init.defaultBranch main

echo "Corporate Git configuration applied"
git config --list | grep user
EOF