# Git Quick Reference

Quick reference guide for common Git operations.

## File Changes and Status

### View Changed Files

```bash
# Show working directory status
git status

# Show short status
git status -s

# List changed files only (unstaged)
git diff --name-only

# List changed files only (staged)
git diff --cached --name-only
# or
git diff --staged --name-only

# Show file change statistics
git diff --stat
git diff --cached --stat
```

### View Detailed Changes

```bash
# View unstaged changes
git diff

# View staged changes
git diff --cached
# or
git diff --staged

# View specific file changes
git diff <file-path>
git diff --cached <file-path>

# View changes between commits
git diff <commit1>..<commit2>
git diff HEAD~1..HEAD

# View changes between branches
git diff main..feature-branch
```

## Staging and Committing

### Add Files to Staging

```bash
# Add specific file
git add <file-path>

# Add all files in directory
git add .

# Add all files in repository
git add -A

# Add files interactively
git add -p

# Add only modified files (not new files)
git add -u
```

### Check Staging Area

```bash
# List files in staging area
git diff --cached --name-only

# Show detailed staged changes
git diff --cached
```

### Commit Changes

```bash
# Simple commit
git commit -m "feat: add user authentication"

# Multi-line commit (macOS/Linux)
git commit -m "$(cat <<'EOF'
feat: add user authentication

- Add OAuth2 support
- Implement JWT tokens
- Add login/logout endpoints
EOF
)"

# Multi-line commit (Windows)
git commit -m "feat: add user authentication" \
  -m "" \
  -m "- Add OAuth2 support" \
  -m "- Implement JWT tokens" \
  -m "- Add login/logout endpoints"

# Commit with automatic staging
git commit -am "fix: resolve issue"

# Amend last commit (before push only!)
git commit --amend -m "new message"
```

## Tag Management

### Create Tags

```bash
# Create annotated tag
git tag -a "1.2.0" -m "feat: add new feature"

# Create lightweight tag
git tag "1.2.0"

# Create tag with multi-line message
git tag -a "1.2.1" \
  -m "fix: resolve connection issue" \
  -m "" \
  -m "- Increase timeout to 30s" \
  -m "- Add retry mechanism"

# Create tag for specific commit
git tag -a "1.2.0" <commit-hash> -m "message"

# Monorepo tag
git tag -a "ios-1.2.0" -m "feat(ios): add feature"
```

### List Tags

```bash
# List all tags
git tag

# List tags with pattern
git tag -l "v1.*"

# List recent tags (sorted)
git tag --list | sort -V | tail -5

# Show tag details
git show <tag-name>
```

### Push Tags

```bash
# Push single tag
git push origin <tag-name>

# Push all tags
git push --tags
# or
git push origin --tags

# Push commit and tag together
git push origin main && git push origin 1.2.0
```

### Delete Tags

```bash
# Delete local tag
git tag -d <tag-name>

# Delete remote tag
git push origin --delete <tag-name>
# or
git push origin :refs/tags/<tag-name>

# Delete multiple tags
git tag -d tag1 tag2 tag3
```

## Branch Operations

### View Branches

```bash
# Show current branch
git branch --show-current

# List local branches
git branch

# List all branches (local + remote)
git branch -a

# List remote branches only
git branch -r

# Show branch with last commit
git branch -v
```

### Create and Switch Branches

```bash
# Create new branch
git branch <branch-name>

# Create and switch to new branch (old way)
git checkout -b <branch-name>

# Create and switch to new branch (modern)
git switch -c <branch-name>

# Switch to existing branch (old way)
git checkout <branch-name>

# Switch to existing branch (modern)
git switch <branch-name>

# Switch to previous branch
git switch -
```

### Delete Branches

```bash
# Delete local branch (safe)
git branch -d <branch-name>

# Delete local branch (force)
git branch -D <branch-name>

# Delete remote branch
git push origin --delete <branch-name>
# or
git push origin :<branch-name>
```

## Pushing and Pulling

### Push Changes

```bash
# Push current branch
git push

# Push to specific remote and branch
git push origin main

# Push current branch to remote
git push origin $(git branch --show-current)

# Push with upstream tracking
git push -u origin <branch-name>

# Push all branches
git push --all

# Push all tags
git push --tags

# Force push (dangerous!)
git push --force
# Better: force push with lease
git push --force-with-lease
```

### Pull Changes

```bash
# Pull from tracked remote
git pull

# Pull from specific remote and branch
git pull origin main

# Pull with rebase
git pull --rebase

# Pull and prune deleted remote branches
git pull --prune
```

### Fetch Changes

```bash
# Fetch from all remotes
git fetch

# Fetch from specific remote
git fetch origin

# Fetch and prune deleted remote branches
git fetch --prune

# Fetch all branches and tags
git fetch --all --tags
```

## History and Logs

### View Commit History

```bash
# View recent commits
git log

# View compact history
git log --oneline

# View recent 10 commits
git log --oneline -10

# View history with graph
git log --graph --oneline --all

# View history with stats
git log --stat

# View history with patches
git log -p
```

### Search History

```bash
# Search commits by message
git log --grep="feature"

# Search by author
git log --author="John"

# Search by date
git log --since="2024-01-01"
git log --after="2 weeks ago"
git log --before="yesterday"

# Search by file
git log -- <file-path>

# Search code changes
git log -S "function_name"
```

### View Commit Details

```bash
# Show specific commit
git show <commit-hash>

# Show specific tag
git show <tag-name>

# Show HEAD commit
git show HEAD

# Show previous commit
git show HEAD~1
git show HEAD^
```

## Undoing Changes

### Discard Changes

```bash
# Discard unstaged changes in file
git checkout -- <file-path>
# or (modern)
git restore <file-path>

# Discard all unstaged changes
git checkout -- .
# or (modern)
git restore .

# Unstage file (keep changes)
git reset HEAD <file-path>
# or (modern)
git restore --staged <file-path>

# Unstage all files
git reset HEAD
# or (modern)
git restore --staged .
```

### Reset Commits

```bash
# Undo last commit, keep changes staged
git reset --soft HEAD~1

# Undo last commit, keep changes unstaged
git reset HEAD~1
# or
git reset --mixed HEAD~1

# Undo last commit, discard changes (dangerous!)
git reset --hard HEAD~1

# Reset to specific commit
git reset --hard <commit-hash>
```

### Revert Commits

```bash
# Create new commit that undoes a commit
git revert <commit-hash>

# Revert without committing
git revert -n <commit-hash>

# Revert multiple commits
git revert <commit1>..<commit2>
```

## Stash Operations

### Save Changes

```bash
# Stash current changes
git stash

# Stash with message
git stash save "work in progress"

# Stash including untracked files
git stash -u

# Stash including untracked and ignored files
git stash -a
```

### Apply Stash

```bash
# Apply most recent stash
git stash apply

# Apply and remove from stash list
git stash pop

# Apply specific stash
git stash apply stash@{2}
```

### Manage Stash

```bash
# List all stashes
git stash list

# Show stash changes
git stash show
git stash show -p

# Drop specific stash
git stash drop stash@{1}

# Clear all stashes
git stash clear
```

## Remote Operations

### View Remotes

```bash
# List remotes
git remote

# List remotes with URLs
git remote -v

# Show remote details
git remote show origin
```

### Manage Remotes

```bash
# Add remote
git remote add <name> <url>

# Remove remote
git remote remove <name>

# Rename remote
git remote rename <old-name> <new-name>

# Change remote URL
git remote set-url <name> <new-url>
```

## Configuration

### View Configuration

```bash
# View all config
git config --list

# View global config
git config --global --list

# View local config
git config --local --list

# View specific config
git config user.name
git config user.email
```

### Set Configuration

```bash
# Set user name
git config --global user.name "Your Name"

# Set user email
git config --global user.email "your.email@example.com"

# Set default branch name
git config --global init.defaultBranch main

# Set default editor
git config --global core.editor "code --wait"

# Set credential helper
git config --global credential.helper store
```

## Workflow Examples

### Standard Commit and Tag Workflow

```bash
# 1. Check status
git status
git diff --cached --name-only

# 2. Stage changes
git add .

# 3. Commit
git commit -m "feat: add user authentication"

# 4. Create tag
git tag -a "1.2.0" -m "feat: add user authentication"

# 5. Push commit and tag
git push origin main
git push origin 1.2.0
```

### Complete Staging to Push Workflow

```bash
# Check what files changed
git status

# View changes
git diff

# Stage specific files
git add src/auth.js src/api.js

# Verify staging
git diff --cached --name-only

# Commit with message
git commit -m "feat: implement OAuth2 authentication"

# Push to remote
git push origin main
```

### Push All Tags Workflow

```bash
# List local tags
git tag

# View recent tags
git tag --list | sort -V | tail -5

# Push all tags to remote
git push --tags

# Verify tags on remote
git ls-remote --tags origin
```

### Quick Status Check

```bash
# Full status
git status

# Changed files only
git diff --name-only
git diff --cached --name-only

# Recent commits and tags
git log --oneline -5
git tag --list | sort -V | tail -5

# Current branch
git branch --show-current
```

## Tips and Tricks

### Aliases

Add to `~/.gitconfig`:

```ini
[alias]
  st = status
  co = checkout
  br = branch
  ci = commit
  unstage = restore --staged
  last = log -1 HEAD
  lg = log --graph --oneline --all
  tags = tag -l --sort=-v:refname
```

Usage:
```bash
git st
git co main
git lg
```

### Useful One-Liners

```bash
# Delete all merged branches
git branch --merged | grep -v "\*" | xargs -n 1 git branch -d

# View file in specific commit
git show <commit>:<file-path>

# Count commits by author
git shortlog -sn

# Find when a line was changed
git blame <file-path>

# Show what changed in each commit for a file
git log -p <file-path>

# List files in a commit
git diff-tree --no-commit-id --name-only -r <commit>
```