.git-monitoring.php

<?php

 $website = 'domain.com';
 $path = '/path/to/htdocs';
 $email = 'name@domain.com';

 $git_status = shell_exec('git --git-dir=' . $path . '/.git --work-tree=' . $path . ' status');
 $git_log = file_exists($path . '/.git-monitoring.log') ? file_get_contents($path . '/.git-monitoring.log') : '';
 if (!preg_match('/working directory clean/ism', $git_status) && $git_log != $git_status) {
  file_put_contents($path . '/.git-monitoring.log', $git_status);
  $git_status = shell_exec('git --git-dir=' . $path . '/.git --work-tree=' . $path . ' status');
  file_put_contents($path . '/.git-monitoring.log', $git_status);
  $mail = 'Git status changed for ' . $website . '. Here is output:' . "\n\n" . $git_status;
  mail($email, 'Git status changed for ' . $website . '.', $mail);
 }