[CentOS] - automation script

Hi everybody,

I have many server in production but I would verify this:

ex.: I have many domain in /var/www/html/ (domain1 / domain2 / domain3)

now,

How I do check if the files are added or changed?
I should apply this "politic" for all domains but I don't know how

It is possible send me an email with the modification?
so, exist diff command with some option but I don't understand how to apply it

Can help me somebody?
Thanks in advance

Regards