a super simple php webhook from http://jonathanstark.com/blog/deploying-code-automatically-with-github-webhooks

php-deploy.php

<?php

// Init vars
$LOCAL_ROOT         = "/var/www/my_new_site";
$LOCAL_REPO_NAME    = "public_html";
$LOCAL_REPO         = "{$LOCAL_ROOT}/{$LOCAL_REPO_NAME}";
$REMOTE_REPO        = "[email protected]:jonathanstark/my_new_site.git";
$DESIRED_BRANCH     = "dev";

// Delete local repo if it exists
if (file_exists($LOCAL_REPO)) {
    shell_exec("rm -rf {$LOCAL_REPO}");
}

// Clone fresh repo from github using desired local repo name and checkout the desired branch
echo shell_exec("cd {$LOCAL_ROOT} && git clone {$REMOTE_REPO} {$LOCAL_REPO_NAME} && cd {$LOCAL_REPO} && git checkout {$BRANCH}");

die("done " . mktime());