Git Advanced

Worktrees

# Create a worktree for a feature branch (avoids stashing)
git worktree add ../feature-auth feature/auth

# Create a worktree with a new branch
git worktree add ../hotfix-123 -b hotfix/123 origin/main

# List all worktrees
git worktree list

# Remove a worktree after merging
git 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

# Start bisect, mark current as bad and known good commit
git bisect start
git bisect bad HEAD
git bisect good v1.5.0

# Git checks out a midpoint commit. Test it, then mark:
git bisect good   # if this commit works
git bisect bad    # if this commit is broken

# Automate with a test script
git bisect start HEAD v1.5.0
git bisect run npm test

# When done, reset
git 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

# Rebase last 5 commits interactively
git rebase -i HEAD~5

# Common operations in the editor:
# pick   - keep commit as-is
# reword - change commit message
# edit   - stop to amend the commit
# squash - merge into previous commit, keep both messages
# fixup  - merge into previous commit, discard this message
# drop   - remove the commit entirely

# Rebase feature branch onto latest main
git fetch origin
git rebase origin/main

# Continue after resolving conflicts
git rebase --continue

# Abort if things go wrong
git rebase --abort

Git Hooks

#!/bin/sh
# .git/hooks/pre-commit

# Run linter on staged files only
STAGED_FILES=$(git diff --cached --name-only --diff-filter=d | grep -E '\.(ts|tsx|js|jsx)$')
if [ -n "$STAGED_FILES" ]; then
  npx eslint $STAGED_FILES --fix
  git add $STAGED_FILES
fi

#!/bin/sh
# .git/hooks/commit-msg