Change Internal Document Links when moving site collection to new location

Question

We have sub-sites in our main site collection that are 20+GB, and need to move them to their own site collection.

Problem is all the Word, Excel, PowerPoint files that have links referencing URLs to the old site collection URL.

Is there a way to use CSOM or something that would loop through the files and update the URLS?

Example of URLs that would be changed:

Current location is >> http://mysparea.com/sites/BigSite/FirstSite

New location would be >> http://mysparea.com/sites/BigSiteFirstSite

What we are trying to do is move the site to it's own site collection and remove a single "/" from the URL.

It's a find/replace for the URL is what we're after.

Answer 1

Alternatively you could try the URL rewrite module of IIS without changing the links inside all documents if it is an on-premises environment.