githooks

Git hooks are executable scripts that Git runs before or after certain events in a repository, such as commits, merges, or pushes. They reside in the .git/hooks directory and can influence the behavior of the local workflow. Git ships with sample hook scripts that illustrate how to implement common checks and actions. Hooks execute on the developer’s machine, and server-side hooks can run on the remote repository to enforce policies when data is received.

Common hooks include pre-commit (runs before a commit is created, often used to run linters or tests), prepare-commit-msg (before the commit message editor opens), commit-msg (validates or formats the commit message), post-commit (after a commit), pre-push (before pushes are sent), and various checkout/merge/rebase related hooks. Hooks are simple programs or scripts written in languages such as shell, Python, or PowerShell, and they must be executable. On Unix-like systems they require execute permission; Windows support depends on the script language and environment.

Since hooks live in a repository’s local .git directory by default, teams often share hook configurations by storing scripts in the repository and configuring Git to use a shared hooks directory via core.hooksPath, or by using tooling to install and manage hooks across environments. Popular frameworks for this purpose include Husky (for JavaScript), pre-commit, Lefthook, and similar solutions.

Best practices emphasize keeping hooks fast and deterministic, providing clear error messages, documenting setup requirements, and testing hooks to avoid disrupting development workflows. Security considerations include limiting trusted scripts and validating inputs to prevent unintended actions. Server-side hooks provide a complementary mechanism to enforce policies on the repository host.