Any time you need to make the same edits in multiple places. I use it to mass edit array items for example by using the highlight / add cursor to identical text feature in VS Code (Ctrl+D). I even use it to copy data out of the browser and mass edit it into data structures-- often there will be some pattern to the pasted data even if it's garbage, so being able to quickly set up multicursors around the patterns in the text makes this sort of task much easier, if you are luckily on how the data pastes out.

Multicursors are the number one editor innovation of the last ten years that developers should get comfortable with-- once you start to use them you won't want to use an editor without them.

Personally while there are some task that's easier with multiple cursors, I have personally yet to find any use case where regexp replace in selections doesn't work as well.

You cannot edit in real-time with regex

With regex, you need to plan everything you need to do and then surgically do it.

With multiple cursors, you only need to know (roughly) where you need to change, the rest you figure it out on the fly.

In editors like vim/emacs it is possible and common.

I find Emacs Macros and rectangular editing as more useful in lore situations than multiple cursors.

As for regexps, the syntax in Emacs is hell, but I do know Emcacs has very powerful edit/replace tools.

Multi-cursor is more flexible than rectangular selection. You can skip or delete words of varying length etc. It is certainly less powerful than vim macro and regex, but it's easy to use because 1) there are less shortcuts to remember 2) no need to think too much like figuring out regex for simple tasks 3) it gives instant feedback

Video showing this https://youtu.be/lhFNWTAIzOI?t=28

skill issue tbh

"Emcacs"...I like it.

Yeah... typing fast and from the phone has this problem

There's a reason people use visual editors and not ed.

Wouldn’t remotely compare regex to ed.

I also haven’t found a use for multiple cursors.

Writing a regex is quick and easy.

I guess with rectangular selection and macros, VIM folks don't find much use for multiple cursors.

I use it to:

* transform a list of field names into different formats (class properties, sql select list, etc.)

* quick and dirty convert delimited text into insert statements or graphql queries or json objects

* really anything I need to change in column mode but with better tracking of words via mod+arrow keys

I use it daily in vscode to clean up small data sets where wrangling regex will take more time, and the data set isn’t something that I’m gonna see again so it’s not worth generalizing a solution.

If you're using the same variable name across the file, but want to change only a couple of references to something else, it fills that "I need to do this more than once, but in a bit of an easier to reach, fancier way than with find and replace" niche.

Most editors these days should have "rename" functionality which is very aware of how that symbol is used across a codebase.

M-x lsp-rename in emacs, for example works great, if you're using lsp.

Yes but this is more general, allowing you to use it in more cases. For instance, I use it heavily when converting old JavaScript to modern ES/TS. Using "var" everywhere? Replace them all with let. Using anonymous functions instead of lambdas, easy to change those all over (provided there's no "this" dependencies)

Have two thousand strings which all need the same edits? No need to do a find/replace operation, you can do it directly in the editor.

How do you select those two thousand strings?

Using VS Code: select whatever you want to match, then Ctrl+Shift+L

So it has to be two thousand identical strings? Then I don’t understand the benefit over search & replace.

It goes further than just that -- for instance, lets say your data looks like this:

    [
        "foo bar/2322",
        "foo baz/4223",
        "foo blah/2232",
        ...
    ]

And you need to reformat that into:

    [
        "bar 2322: foo",
        "baz 4223: foo",
        "blah 2232: foo",
        ...
    ]

You can absolutely use a regular expression find/replace to solve this. But using multicursors, you can just highlight the first "foo ", then hold Ctrl+D to select all instances, then hit right arrow key so that your cursors are at "foo |bar/2322" (and nothing is selected) et al, then use shift+right arrow key to select bar, baz, blah, and all other substrings, then use ctrl+X to cut that list to your clipboard. Hit delete key to get rid of the /s and add a space so you can keep the fields separated. Then, use ctrl+arrow to move your cursors to just before foo ("|foo /2322"), paste, hit space. Now you have "bar foo 2322". Repeat the same action to cut all the "foo" substrings, then move your cursor to the end, now type ": " and then paste.

You get the idea. It sounds complex, but these are all just comprised of the same fundamental editing patterns-- all of the cursors act as if you had just that one cursor when you press the keys. You have to play with multicursors to really appreciate their power.

Most of the time, someone who is well versed with multicursors and their editor's cursor shortcuts (arrow keys, page up/down, shift/ctrl arrow keys, etc) will be able to complete these sort of textual manipulations much faster than using find/replace.

Okay, that particular use case I know as column or vertical select mode.

you can have rows between the columns is the key difference

It doesn't have to be identical. For the method they're describing you just have to get search results -- so you can use regex in that. You can also just command-click anywhere you want to leave a new selection-point. (Or use various other find commands that search for things and add them to your selection pool.)

The benefit of it is that you're left with a cursor in each location, and you can then do absolutely anything that you'd normally do with a single cursor in every place at once. This includes things like copy/paste, which will maintain a separate buffer in each selection. This also includes things that're actually tough to do with normal find/replace -- I could select the bit after a search result and switch it to title-case, for instance.

You can do most things you'd use it for with find/replace. But sometimes it's easier to watch it happen as you type, rather than construct a fairly complex regex with groups and suchlike.

> Have two thousand strings which all need the same edits? No need to do a find/replace operation, you can do it directly in the editor.

I might be missing something here, but how is making 2000 individual selections better than `:%s/oldstring/newstring/g`?

I'm guessing that you have a rule for setting up those 2000 selection, or something?

I mean, even for like 5 identical edits, the regex is going to be faster, so you must have a short way of performing the multi-selection.

It helps when it is a bit more interactive, i.e when I only need to replace some of the occurrences versus everything.

Also when working with lists it is useful, you spawn cursors on , or < or whatever symbol you've got at a fixed location between lines, and then you can manipulate text in any number of otherwise different lines.

I use it all the time to mangle small amounts of data, like selecting all the newlines in a file with cntrl-d and making them into "," to make it into values for an array or something (obv. search+replace could do that, still it's quicker for a small number this way, or feels like it). It was pretty slick in the early TextMate / Sublime days to see people editing html and making a big bunch of tags all write themselves out simultaneously.

been a while since I used it, but it was handy for templates where you need to enter a name once and have it typed in multiple places in the template (quicker than a find/replace). It was a also handy sometimes to just be able to put your cursor on the name of a variable or bigger text selection, smash cmd+d a handful of times to add another cursor at every other occurrences of it in the file, and then just start typing to modify each of those occurrences.