Batch replace values in content files

What are my options for batch changing content? I want to search for specific values, and change only those. I could download the files on my computer and perform the edits with my code editor, but are there any alternatives for content that is already online?

It’s not a good idea to do something like that on a production server. No matter if you do this using replace or programmatically. I guess you want to permanently replace those values, not change them at runtime?

@pixelijn The issue concerns hundreds of pages which queried tag options from a certain page. The stored tag for all of these pages must have its value changed. So the change will be permanent. I guess the safest way is to download all content, do replacing and re-upload.