Undoing Changes

Quick Summary

Git provides ways to undo changes at every level — from discarding uncommitted edits to rewriting entire commit histories. The right tool depends on what you want to undo and whether the changes have been shared.

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Undo Decision Flowchart

flowchart TD
    A["What do you want to undo?"] --> B{Pushed to remote?}
    B -->|No| C{Committed?}
    B -->|Yes| D["git revert<br/>(safe, creates new commit)"]
    C -->|No| E{Staged?}
    C -->|Yes, last commit| F["git commit --amend<br/>or git reset"]
    C -->|Yes, older commit| G["git rebase -i"]
    E -->|No| H["git checkout -- file<br/>or git restore file"]
    E -->|Yes| I["git restore --staged file<br/>or git reset HEAD file"]

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By Severity Level

Level 1: Discard Unstaged Changes (Working Directory)

# Discard changes to a specific file
git restore <file>
git checkout -- <file>    # Legacy equivalent

# Discard ALL unstaged changes
git restore .
git checkout -- .         # Legacy

This is irreversible

Discarding unstaged changes permanently deletes your modifications. There's no undo for this undo.

Level 2: Unstage Files (Keep Changes)

# Unstage a specific file (keep modifications in working directory)
git restore --staged <file>
git reset HEAD <file>     # Legacy equivalent

# Unstage everything
git restore --staged .
git reset HEAD            # Legacy

Level 3: Amend the Last Commit

# Fix the commit message
git commit --amend -m "Corrected message"

# Add forgotten files to the last commit
git add forgotten-file.js
git commit --amend --no-edit

# Change author
git commit --amend --author="Name <email>" --no-edit

Level 4: Undo Commits (Local Only)

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

# Undo last commit, keep changes unstaged
git reset --mixed HEAD~1   # (default)
git reset HEAD~1

# Undo last commit, DELETE all changes
git reset --hard HEAD~1

Reset Mode	Commit	Staging	Working Directory
--soft	❌ Undone	✅ Preserved	✅ Preserved
--mixed (default)	❌ Undone	❌ Unstaged	✅ Preserved
--hard	❌ Undone	❌ Cleared	❌ Deleted

Level 5: Undo Pushed Commits (Safe)

# Create a NEW commit that reverses the changes of a specific commit
git revert <commit-hash>

# Revert the last commit
git revert HEAD

# Revert without auto-committing
git revert --no-commit <hash>

# Revert a merge commit (specify parent)
git revert -m 1 <merge-commit-hash>

Revert vs Reset

revert creates a new commit that undoes changes — safe for shared branches.
reset rewrites history — only safe for local, unpushed commits.

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Common Undo Scenarios

Scenario	Command
Accidentally edited a file	git restore <file>
Staged wrong files	git restore --staged <file>
Commit message typo	git commit --amend -m "..."
Forgot to include a file	git add file && git commit --amend --no-edit
Want to redo last commit differently	git reset --soft HEAD~1
Need to undo a pushed commit	git revert <hash>
Accidentally deleted a branch	git reflog + git branch recover <hash>
Bad merge	git revert -m 1 <merge-hash>

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Best Practices

• Use git restore (Git 2.23+) instead of the overloaded git checkout for discarding changes
• Use revert for shared history — never reset --hard on pushed commits
• Check git status before dangerous operations — know what you're undoing
• Keep reflog in mind — your last resort for recovering "lost" commits

What's Next

1. Recovery Techniques — Recover deleted branches, lost commits, and corrupted repos
2. Cheatsheet — Quick reference for all Git commands