Git Hooks: Automate Tasks on Git Events

What Are Git Hooks?

Git hooks are scripts that run automatically when specific Git events occur — such as committing, pushing, or merging. They live in the .git/hooks/ directory and can be written in any scripting language (bash, Python, Node.js, etc.).

Common Client-Side Hooks

Hook	Trigger	Common Use
pre-commit	Before commit is created	Lint, format, type-check
commit-msg	After message is written	Validate commit message format
pre-push	Before push to remote	Run tests
post-merge	After a merge completes	Install dependencies
post-checkout	After branch switch	Notify, rebuild

Creating a Pre-Commit Hook

# .git/hooks/pre-commit
#!/bin/sh
npm run lint
if [ $? -ne 0 ]; then
  echo "Linting failed. Commit aborted."
  exit 1
fi

chmod +x .git/hooks/pre-commit

Sharing Hooks with the Team

Hooks in .git/hooks/ are not committed to the repository. To share them:

1. Store hooks in a committed directory (e.g., .githooks/).
2. Configure Git to use that directory:

git config core.hooksPath .githooks

Popular Hook Frameworks

• Husky (Node.js) — the most popular for JavaScript projects.
• pre-commit (Python) — language-agnostic with a large plugin ecosystem.
• lefthook (Go) — fast, parallel hook execution.

Server-Side Hooks

Hooks can also run on the server (e.g., GitLab, self-hosted Git):

Hook	Trigger
pre-receive	Before accepting a push
post-receive	After accepting a push
update	Per-branch, before updating ref

Tips

Keep hooks fast — slow pre-commit hooks frustrate developers and get bypassed. Run heavy tasks (full test suites) in pre-push instead. Git hooks are the first line of defense for code quality.