Creating custom hook scripts in Git - Step-by-Step CLI Walkthrough

Introduction

Sometimes you want Git to do extra checks or actions automatically when you commit or push code. Custom hook scripts let you add these automatic steps to help keep your code safe and organized.

When you want to check code style before allowing a commit

When you want to run tests automatically before pushing code

When you want to send a notification after a successful push

When you want to prevent commits with sensitive data like passwords

When you want to enforce commit message formats

Commands

Go to the hooks folder inside your Git repository where hook scripts live.

Terminal

cd .git/hooks

Expected Output

No output (command runs silently)

Create a simple pre-commit hook script that prints a message before a commit.

Terminal

echo '#!/bin/sh\necho "Running pre-commit hook"' > pre-commit

Expected Output

No output (command runs silently)

Make the pre-commit script executable so Git can run it.

Terminal

chmod +x pre-commit

Expected Output

No output (command runs silently)

→

+x - Makes the script executable

Try to commit changes to see the pre-commit hook run and print its message.

Terminal

git commit -m "test commit"

Expected Output

Running pre-commit hook

[main abc1234] test commit

 1 file changed, 1 insertion(+)

Key Concept

If you remember nothing else from this pattern, remember: Git hooks are scripts placed in the .git/hooks folder that run automatically at specific points in Git workflows.

Common Mistakes

Not making the hook script executable

Git will not run the script if it does not have execute permission.

Use chmod +x on the hook script to make it executable.

Naming the hook script incorrectly

Git only runs scripts with exact hook names like pre-commit, post-commit, etc.

Name the script exactly as the hook you want to use, e.g., pre-commit.

Writing hook scripts in unsupported languages without a proper shebang

Git needs the script to start with a shebang (like #!/bin/sh) to know how to run it.

Start your script with a shebang line for the language you use.

Summary

Navigate to the .git/hooks directory to manage hook scripts.

Create a script with the exact hook name, like pre-commit, to run at that event.

Make the script executable with chmod +x so Git can run it automatically.