Git hooks are usually found inside the .git/hooks folder of your git repository. Git tends to provide sample hook files there which are postfixed with a .sample extension. These examples are written as shell scripts. Take a look at them if you want, but today we're talking PHP!

He briefly touches on the types of hooks you can set up and includes two example scripts showing a pre-commit lint test for the changed files and a check during the commit on the message given for a certain standard (in their case, it must start with a three letter code).