I'm not sure what you mean by CMU? It's also unclear if you're alraedy using concrete5 and are looking to do a find and replace on the contents of concrete5 blocks or if you have some other system that exists that you're trying to modify.

Generally, I don't recommend people unfamiliar with the intricacies of a database doing bulk find/replace on any database tables/fields. This is a VERY dangerous thing to do if you don't know exactly what you're doing and what the side effects might be. It can be done using MySQL's REPLACE() function, but please make sure you take a database backup prior to attempting such things.
https://www.exchangecore.com/blog/mysql-find-and-replace-values/...

Generally, if this is something you will be doing frequently it likely means there is a better process that can/should be created. Consider hiring a developer to develop something that meets your specific needs rather than trying to force a system to do something it wasn't intended to.

I will add to what @exchangecore sais that is absolutely correct that you are also looking into opening and parsing an excel file through code and scrapping a website. Nothing trivial

I realise this is an old thread, but just in case someone stumbles across it, I have a new add-on that does a great job of finding & replacing content across the entire website - all blocks and all page attributes. Here's a link:https://www.concrete5.org/marketplace/addons/find-and-replace/...