git diff Command Guide

# Show unstaged changes
git diff

# Show staged changes (ready for commit)
git diff --staged
git diff --cached  # Same as --staged

# Show all changes (staged + unstaged)
git diff HEAD

# Working directory vs staging area
git diff

# Staging area vs last commit
git diff --staged

# Working directory vs last commit
git diff HEAD

# Working directory vs specific commit
git diff abc1234

# Between two commits
git diff abc1234 def5678
git diff abc1234..def5678  # Same thing

# Specific file
git diff -- file.js
git diff HEAD -- file.js

# Changes between branches
git diff main..feature

# What's in feature that's not in main
git diff main...feature

# Compare with remote branch
git diff origin/main

# Before merging, see what would change
git diff HEAD...origin/main

# Compare specific file across branches
git diff main..feature -- src/app.js

# Review before committing
git diff --staged

# Quick summary of changes
git diff --stat

# See what files changed
git diff --name-only HEAD~3

# Ignore whitespace changes
git diff -w

# Word-level diff (useful for prose)
git diff --word-diff

# Compare with last week
git diff HEAD@{1.week.ago}

# Export diff as patch
git diff > changes.patch

# Check if there are changes
git diff --quiet || echo "Changes detected"