# Change only the commit message
git commit --amend -m "New improved commit message"

# Open editor to modify commit message
git commit --amend

# Add forgotten files and amend
git add forgotten-file.js
git commit --amend --no-edit

# Add changes and update message
git add updated-file.js
git commit --amend -m "Updated commit with additional changes"

# Open editor for both message and staged changes
git add .
git commit --amend

# Original commit with typo
git commit -m "Fix user athentication bug"

# Amend to fix typo
git commit --amend -m "Fix user authentication bug"

# Made a commit but forgot to include a file
git commit -m "Add user registration feature"

# Add the forgotten file
git add registration.test.js
git commit --amend --no-edit

# Commit initial implementation
git commit -m "Implement password validation"

# Realize you need to improve the implementation
git add password-validator.js
git commit --amend -m "Implement improved password validation"

# Accidentally committed debug files
git commit -m "Add user dashboard"

# Remove debug files from commit
git reset HEAD~1
git add dashboard.js  # Add only the files you want
git commit -m "Add user dashboard"

# Change author of last commit
git commit --amend --author="New Author <new@email.com>"

# Change author and message
git commit --amend --author="John Doe <john@example.com>" -m "Updated commit"

# Update commit date to current time
git commit --amend --date="$(date)"

# Set specific date
git commit --amend --date="2023-12-01 10:00:00"

# Create empty commit (useful for triggering CI)
git commit --allow-empty -m "Trigger CI build"

# Amend to add content later
git add files.js
git commit --amend -m "Add feature and trigger CI"

# ❌ DON'T amend commits that have been pushed to shared repos
git push origin main
git commit --amend  # This will cause problems for other developers

# ✅ DO amend commits only on local/feature branches
git checkout feature-branch
git commit --amend  # Safe on feature branches before sharing

# Review what you're about to amend
git diff --staged
git show HEAD

# Then amend
git commit --amend

# Always test after amending
git commit --amend
npm test  # or your test command
git push origin feature-branch

# ❌ Poor amend message
git commit --amend -m "fix"

# ✅ Good amend message
git commit --amend -m "fix: resolve user authentication timeout issue"

# 1. Start working on feature
git checkout -b feature/user-profile
git add profile.js
git commit -m "Add user profile component"

# 2. Realize you forgot tests
git add profile.test.js
git commit --amend -m "Add user profile component with tests"

# 3. Code review feedback - improve implementation
git add profile.js
git commit --amend -m "Add user profile component with tests and improved validation"

# 4. Ready to push
git push origin feature/user-profile

# 1. Fix bug
git add bug-fix.js
git commit -m "Fix login validation bug"

# 2. Add regression test
git add login.test.js
git commit --amend -m "Fix login validation bug and add regression test"

# 3. Update documentation
git add README.md
git commit --amend -m "Fix login validation bug, add test, and update docs"

# If you made a mistake amending
git reflog
# Find the commit before your amend (usually HEAD@{1})
git reset --hard HEAD@{1}

# Create backup branch before major amends
git branch backup-before-amend
git commit --amend -m "New message"

# If something goes wrong, recover
git reset --hard backup-before-amend

# Amend: Modify last commit in place
git commit --amend

# Reset: Move to previous commit, optionally keeping changes
git reset --soft HEAD~1  # Keep changes staged
git reset --mixed HEAD~1  # Keep changes unstaged
git reset --hard HEAD~1   # Discard changes

# Amend: Modify the commit (for unpublished commits)
git commit --amend

# Revert: Create new commit that undoes changes (for published commits)
git revert HEAD

# Amend: Quick fix for last commit only
git commit --amend

# Interactive Rebase: Modify multiple commits
git rebase -i HEAD~3

# Quick amend without editing message
git config --global alias.amend "commit --amend --no-edit"

# Amend with editor
git config --global alias.amendd "commit --amend"

# Add all and amend
git config --global alias.amendall "!git add -A && git commit --amend --no-edit"

# Review staged changes
git config --global alias.staged "diff --staged"

# Error: nothing to commit, working tree clean
# Solution: Stage changes first
git add files-to-change.js
git commit --amend

# Error after force push needed
# Solution: Use force-with-lease for safety
git push --force-with-lease origin feature-branch

# Use reflog to recover
git reflog
git reset --hard HEAD@{1}  # Go back to before amend

#!/bin/sh
# .git/hooks/pre-commit
# Ensure tests pass before allowing amend
if [ "$GIT_EDITOR" = ":" ]; then
    # This is likely an amend, run tests
    npm test
fi

# Set up commit message template
git config --global commit.template ~/.gitmessage

# ~/.gitmessage content:
# <type>: <description>
# 
# [optional body]
# 
# [optional footer]