I think this is a key feature that seems core to a text editor. I’m going to move this to the Feature Requests category.
I think there are plenty of ways to accomplish this, and users could backup their vault prior if they were worried about unintended effects.
Agree!
Find an alternative while waiting for the feature :
Totally agree. Subtree-wise search and replace is really a critical feature that’s missing. Hope it will be implemented soon!
Thousand upvotes.
I come from CRM, where, basically, you manage clients, calls, contacts, contracts, all kinds of labelled and tagged information. Imagine selling a CRM without the ability to make a quick change on the status or label of a 50 or 500-item found set of contacts. You’d never be able to.
I know O is not a CRM, but you know what, I’m going to make it one, because the rest of it is exactly what I need.
But something as rudimentary as changing the tags on 10 found entries, for example-- it’s astounding that I can’t do that, really. For an app that has so many of the obvious bases covered.
Yes, I know about the 2-3 workarounds, but they are just that.
And-- extending this request to also taking a found set after a query, and right clicking on that found set (which you can’t do) like you can in the obsidian file manager, and choosing “move selected items to folder…” or something like that.
That to me is just as much “mass search and replace” – you’re looking for a certain condition (search tag, keywords, regex, etc.), finding that set, and then ACTING on that set (swap tags, delete tags, replace whole phrases, or even move the very file to a slightly different relative folder location)
Why have the ability to create and use folders, when you can only act on items piecemeal? Why have the wonderful search capability we have, without then being able to do something with the found set at all!? (I don’t count merely copying a text list or outline as something)
I mean, it’s veritably barbaric (You have to say that like Mr Howell on Gilligan’s Island)!
Lord, I apologize. 
It will be nice to also have an option for Regular Expression (regexp) Search and Replace.
It will be useful in a knowledge badge project.
+1 for feature
I think it’s worth mentioning, for some users at least, that external text editors can handle this now. I didn’t find a topic on general global search and replace in this forum. The other topic mentioned refers specifically to internal links.
I use Notepad++ on Windows to search and replace across the vault. It includes the ability to filter file types and can use regular expressions. Standard disclaimer applies: Back up first before doing a global replace, check after replacing, yadda, yadda.
There are Mac and Linux tools.
I am on MacOS and use VS Code.
As people have mentioned already, you can use a workaround by doing it on a code editor e.g. install Atom editor, open project → your Obsidian vault folder, Ctrl+Shift+F to search and replace all instances inside this folder.
VS Code. Ctrl + Shift + H works well for this. 
When this will be implemented?
Atleast, Whether is it in the timeline?
@Klaas you are an insider, isn’t it? Can you please ask Devs to work on this if they aren’t already on it. Just atleast raise this feature request in the insider group.
@ViaAhmed: yes I am an Insider, no, I cannot ask the Devs what you want because it does not work like that. Being an Insider only means I get to see new features before those who have not paid.
Licat decides himself what he does when, even the moderators cannot interfere !
Ok, thanks for your clarification. So now, we will just wait for it, no problem.
@ViaAhmed: yes. It is on the so-called roadmap, it was even moved from long term to short term, but then Obsidian mobile came up and was given priority.
So, I don’t know how short/long is “short term”.
On Mac OS or Linux, or using the Windows Subsystem for Linux (WSL), the sed command makes an excellent workaround that allows for regular expressions.
I recommend anyone with a need to batch edit files learn some of sed. Most of us will run into use cases that go beyond anything we could reasonably expect an application, or even a plugin, to cover. sed is a great Swiss Army knife for text manipulation with tons of support online.
Originally I planned to share a command that I recently ran to delete one of my metadata categories. Decided against this:
sed anyhow to make sure I am not trolling you by wrecking your computer.