Git Advanced

Worktrees

bash
1# Create a worktree for a feature branch (avoids stashing)
2git worktree add ../feature-auth feature/auth
3
4# Create a worktree with a new branch
5git worktree add ../hotfix-123 -b hotfix/123 origin/main
6
7# List all worktrees
8git worktree list
9
10# Remove a worktree after merging
11git worktree remove ../feature-auth

Worktrees let you work on multiple branches simultaneously without stashing or committing WIP. Each worktree has its own working directory but shares the same .git repository.

Bisect

bash
1# Start bisect, mark current as bad and known good commit
2git bisect start
3git bisect bad HEAD
4git bisect good v1.5.0
5
6# Git checks out a midpoint commit. Test it, then mark:
7git bisect good   # if this commit works
8git bisect bad    # if this commit is broken
9
10# Automate with a test script
11git bisect start HEAD v1.5.0
12git bisect run npm test
13
14# When done, reset
15git bisect reset

Bisect performs binary search across commits to find which commit introduced a bug. Automated bisect with run is the fastest approach.

Interactive Rebase

bash
1# Rebase last 5 commits interactively
2git rebase -i HEAD~5
3
4# Common operations in the editor:
5# pick   - keep commit as-is
6# reword - change commit message
7# edit   - stop to amend the commit
8# squash - merge into previous commit, keep both messages
9# fixup  - merge into previous commit, discard this message
10# drop   - remove the commit entirely
11
12# Rebase feature branch onto latest main
13git fetch origin
14git rebase origin/main
15
16# Continue after resolving conflicts
17git rebase --continue
18
19# Abort if things go wrong
20git rebase --abort

Git Hooks

bash
1#!/bin/sh
2# .git/hooks/pre-commit
3
4# Run linter on staged files only
5STAGED_FILES=$(git diff --cached --name-only --diff-filter=d | grep -E '\.(ts|tsx|js|jsx)$')
6if [ -n "$STAGED_FILES" ]; then
7  npx eslint $STAGED_FILES --fix
8  git add $STAGED_FILES
9fi

bash
1#!/bin/sh
2# .git/hooks/commit-msg
3
4# Enforce conventional commit format
5COMMIT_MSG=$(cat "$1")
6PATTERN="^(feat|fix|docs|style|refactor|test|chore)(\(.+\))?: .{1,72}$"
7
8if ! echo "$COMMIT_MSG" | head -1 | grep -qE "$PATTERN"; then
9  echo "Error: Commit message must follow Conventional Commits format"
10  echo "Example: feat(auth): add OAuth2 login flow"
11  exit 1
12fi

bash
1#!/bin/sh
2# .git/hooks/pre-push
3
4# Run tests before pushing
5npm test
6if [ $? -ne 0 ]; then
7  echo "Tests failed. Push aborted."
8  exit 1
9fi

Recovery Techniques

bash
1# Undo last commit but keep changes staged
2git reset --soft HEAD~1
3
4# Recover a deleted branch using reflog
5git reflog
6git checkout -b recovered-branch HEAD@{3}
7
8# Recover a file from a specific commit
9git checkout abc1234 -- path/to/file.ts
10
11# Find lost commits (dangling after reset or rebase)
12git fsck --lost-found
13git show <dangling-commit-sha>
14
15# Undo a rebase
16git reflog
17git reset --hard HEAD@{5}  # point before rebase started

Useful Aliases

bash
1# ~/.gitconfig
2[alias]
3  lg = log --graph --oneline --decorate --all
4  st = status -sb
5  co = checkout
6  unstage = reset HEAD --
7  last = log -1 HEAD --stat
8  branches = branch -a --sort=-committerdate
9  stash-all = stash push --include-untracked
10  conflicts = diff --name-only --diff-filter=U

Anti-Patterns

• Force-pushing to shared branches without --force-with-lease
• Rebasing commits that have already been pushed and shared
• Committing large binary files without Git LFS
• Using git add . without reviewing git diff --staged
• Not using .gitignore for build artifacts, dependencies, and secrets
• Keeping long-lived feature branches instead of merging frequently

Checklist

• Worktrees used for parallel branch work instead of stashing
• git bisect run automates bug-finding with a test command
• Interactive rebase cleans up commits before merging to main
• Pre-commit hooks run linting on staged files
• Commit message format enforced via commit-msg hook
• --force-with-lease used instead of --force when force-pushing
• Reflog consulted before any destructive operation
• .gitignore covers build outputs, dependencies, and environment files