Advanced Recovery: Git Lifelines in 20 Minutes

Working Directory  →  Staging Area  →  Repository
     (git add)          (git commit)
     
     ↓ Undo with:        ↓ Undo with:      ↓ Undo with:
   git restore       git restore --staged   git reset/revert

# See what's changed
git status
git diff

# Restore single file to last commit
git restore filename.txt

# Restore all changes in working directory
git restore .

# Restore specific directory
git restore src/

# Keep changes but create backup first
cp important-file.txt important-file.backup
git restore important-file.txt

# Unstage single file
git restore --staged filename.txt

# Unstage all files
git restore --staged .

# Check staging area
git diff --staged

# Choose which parts of a file to restore
git restore -p filename.txt

# Git will ask for each change:
# Restore this hunk [y,n,q,a,d,/,e,?]?
# y = yes, n = no, q = quit, a = all, d = don't restore any

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

# What this does:
# - Moves branch pointer back one commit
# - Keeps all changes in staging area
# - Useful for fixing commit messages or adding forgotten files

# Example workflow:
git reset --soft HEAD~1
# Edit files or stage more changes
git commit -m "Better commit message with all changes"

# Undo last commit, unstage changes (DEFAULT)
git reset HEAD~1
# Same as: git reset --mixed HEAD~1

# What this does:
# - Moves branch pointer back
# - Unstages changes
# - Keeps changes in working directory for editing

# Example: Split one large commit into smaller ones
git reset HEAD~1
git add specific-file.txt
git commit -m "First logical change"
git add other-files.txt
git commit -m "Second logical change"

# ⚠️ DANGER: This permanently deletes changes
git reset --hard HEAD~1

# What this does:
# - Moves branch pointer back
# - Discards staged changes
# - Discards working directory changes
# - NO UNDO without reflog

# Use cases:
# - Experimental branch you want to abandon
# - Returning to known good state
# - Emergency "undo everything" scenario

# Reset to specific commit hash
git reset --hard abc1234

# Reset to branch/tag
git reset --hard origin/main
git reset --hard v1.0.0

# Reset multiple commits
git reset --soft HEAD~3  # Undo last 3 commits

# Revert the most recent commit
git revert HEAD

# Revert specific commit
git revert abc1234

# Revert without automatic commit (review first)
git revert --no-commit HEAD

# Revert a range of commits
git revert HEAD~3..HEAD  # Revert last 3 commits

# Revert merge commit (specify parent)
git revert -m 1 HEAD  # Revert to first parent
git revert -m 2 HEAD  # Revert to second parent

# Usually parent 1 is main branch, parent 2 is feature branch

# Choose which changes to revert
git revert --no-commit HEAD
git restore --staged unwanted-file.txt
git commit -m "Revert most changes except unwanted-file.txt"

# View reflog
git reflog

# Sample output:
# a1b2c3d HEAD@{0}: commit: Add user authentication
# e4f5g6h HEAD@{1}: reset: moving to HEAD~1
# i7j8k9l HEAD@{2}: commit: Fix login bug
# m0n1o2p HEAD@{3}: merge: Fast-forward

# Find the commit you want to recover
git reflog

# Restore to specific reflog entry
git reset --hard HEAD@{2}

# Create branch from reflog entry
git branch recovered-work HEAD@{3}

# Show what changed at specific reflog entry
git show HEAD@{1}

# Show reflog for specific branch
git reflog show feature-branch

# Show reflog for all references
git reflog --all

# Restore deleted file
git restore deleted-file.txt

# Or use checkout (older Git versions)
git checkout HEAD deleted-file.txt

# Find when file was deleted
git log --oneline --follow -- deleted-file.txt

# Restore file from before deletion
git show HEAD~2:deleted-file.txt > recovered-file.txt

# Or restore directly to working directory
git restore --source=HEAD~2 deleted-file.txt

# Search for file across all commits
git log --all --full-history -- "**/filename*"

# Show file content at specific commit
git show commit-hash:path/to/file.txt

# List all files in a commit
git ls-tree -r commit-hash

# Git usually tracks renames automatically
git log --follow renamed-file.txt

# If rename tracking fails, search by content
git log -p --all -S "unique string from file"

# IMMEDIATE ACTION - if not pushed yet:
git reset --hard HEAD~1

# If already pushed - need to rewrite history:
git reset --hard HEAD~1
git push --force-with-lease origin main

# ⚠️ WARNING: Force push affects everyone!
# Better: Use git-filter-branch or BFG Repo-Cleaner

# Step 1: Don't panic, check reflog
git reflog

# Step 2: Find your lost commits
git log --oneline --all --graph --decorate

# Step 3: Recover the commit
git checkout lost-commit-hash
git branch recover-my-work  # Create branch to save it
git switch main
git merge recover-my-work

# If merge hasn't been pushed:
git reset --hard HEAD~1

# If merge was pushed:
git revert -m 1 HEAD  # Revert the merge

# See the divergence
git log --oneline --graph --all

# Option 1: Merge main into your branch
git switch your-branch
git merge main

# Option 2: Rebase your branch onto main
git switch your-branch
git rebase main

# Option 3: Start over with your changes
git switch main
git pull origin main
git checkout your-branch -- .  # Copy files only
git switch main
git switch -c new-clean-branch
# Manual commit of your changes

# List all stashes
git stash list

# Show stash content
git stash show -p stash@{0}

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

# Recover dropped stash (if reflog available)
git fsck --unreachable | grep commit | cut -d' ' -f3 | xargs git log --merges --no-walk

# Start bisect to find problematic commit
git bisect start
git bisect bad          # Current commit is broken
git bisect good v1.0    # This version was working

# Git checks out middle commit - test it
# If broken: git bisect bad
# If working: git bisect good
# Repeat until you find the exact commit

git bisect reset  # Return to original state

# Apply specific commit to current branch
git cherry-pick abc1234

# Apply multiple commits
git cherry-pick commit1 commit2 commit3

# Cherry-pick without committing (review first)
git cherry-pick --no-commit abc1234

# Create separate working directory
git worktree add ../experimental-fix

# Work in the new worktree without affecting main
cd ../experimental-fix
# Make changes safely

# Remove worktree when done
git worktree remove ../experimental-fix

git restore file.txt           # Discard working changes
git restore --staged file.txt  # Unstage file
git stash                      # Save work temporarily
git stash pop                  # Restore stashed work

git reset --soft HEAD~1        # Undo commit, keep changes staged
git reset HEAD~1               # Undo commit, keep changes unstaged
git reset --hard HEAD~1        # ⚠️ Undo commit, discard changes
git commit --amend            # Fix last commit message/content

git revert HEAD               # Safely undo last commit
git revert abc1234           # Safely undo specific commit
git revert HEAD~3..HEAD      # Revert range of commits

git reflog                   # See all HEAD movements
git reset --hard HEAD@{3}    # Go back to reflog entry
git branch recovery abc1234  # Create branch from lost commit
git fsck --lost-found        # Find truly lost objects

# Set up helpful aliases
git config --global alias.undo 'reset HEAD~1 --mixed'
git config --global alias.amend 'commit -a --amend'
git config --global alias.wipe 'reset --hard HEAD'
git config --global alias.save 'stash push -u'
git config --global alias.load 'stash pop'