Undoing Changes

🤔 Three Levels of “Undo”

Git has different undo tools depending on where the change is:

Working directory — files you edited but haven’t staged
Staging area — files you git add-ed but haven’t committed
Repository — commits you already made

flowchart TB
    subgraph Undo[Undoing Changes]
        direction LR
        WD["Working Directory<br/>Discard changes"] --> SA["Staging Area<br/>Unstage files"]
        SA --> REPO["Repository<br/>Undo commits"]
    end

    subgraph Commands[Which Command?]
        RESTORE["git restore &lt;file&gt;<br/>Discard unstaged changes"]
        UNSTAGE["git restore --staged &lt;file&gt;<br/>Unstage (keep changes)"]
        RESET["git reset --soft/mixed/hard<br/>Move branch pointer"]
        REVERT["git revert &lt;commit&gt;<br/>New commit that undoes"]
    end

    WD --> RESTORE
    SA --> UNSTAGE
    REPO --> RESET
    REPO --> REVERT

    style Undo fill:#7c3aed,color:#fff
    style RESTORE fill:#3b82f6,color:#fff
    style UNSTAGE fill:#f59e0b,color:#fff
    style RESET fill:#ef4444,color:#fff
    style REVERT fill:#10b981,color:#fff

🔄 git restore — Discard Local Changes

# Discard changes in working directory (go back to last commit)
git restore index.html

# Unstage a file (but keep the changes)
git restore --staged index.html

# Unstage AND discard changes
git restore --staged --worktree index.html

↩️ git reset — Move the Branch Pointer

reset moves the current branch back to a previous commit. It comes in three flavors:

# ─── SOFT — move pointer back, keep everything staged ───
git reset --soft HEAD~1
# Changes are still in the staging area

# ─── MIXED (default) — move pointer, unstage, keep files ───
git reset --mixed HEAD~1
# git reset HEAD~1           (same thing)
# Changes are in working directory

# ─── HARD — DELETE changes permanently ⚠️ ───
git reset --hard HEAD~1
# Changes are GONE. Can't recover (usually)

Visual:

Before reset (HEAD is at D):
    A ──▶ B ──▶ C ──▶ D
                        ▲
                       HEAD

After git reset --hard HEAD~2:
    A ──▶ B
            ▲
           HEAD
    (C and D are discarded)

↩️ git revert — Safe Undo (Recommended)

revert creates a new commit that undoes a previous commit. It doesn’t rewrite history.

# Revert the last commit
git revert HEAD
# Creates a new commit "Revert 'Add login page'"

# Revert a specific commit
git revert a1b2c3d

# Revert multiple commits
git revert HEAD~3..HEAD

Before revert:
    A ──▶ B ──▶ C ──▶ D (HEAD)

After revert:
    A ──▶ B ──▶ C ──▶ D ──▶ E (HEAD)
                                │
                                └── "Revert C — Remove login page"

Result: Commit C’s changes are undone, but the history is preserved. Everyone can git pull safely.

📊 reset vs revert

	`git reset`	`git revert`
Rewrites history?	✅ Yes	❌ No
Safe for shared branches?	❌ No	✅ Yes
Creates a new commit?	❌ No	✅ Yes
Use when…	Local changes you haven’t pushed	Commits already pushed to shared branch

Golden rule: Use revert for anything pushed to shared branches. Use reset for local work only.

In Simple Words

git restore — discard file changes in working directory or unstage files
git reset --soft/mixed/hard — move branch pointer back (rewrites history)
git revert <commit> — creates a new undo commit (safe for shared branches)
Use revert for pushed commits; use reset for local work only
--hard is dangerous — it permanently deletes uncommitted changes