I believe that's only on MacOS.

I think Microsoft Office (maybe jiat Word, but definitely not Windows) has a similar default shortcut.

You don't need a shortcut on Word.

You just type two hyphens (--) and Word will convert it to an em dash.

Across the Office suite:

Typing <word><hyphenminus><hyphenminus><word><space> yields an em dash.

Typing <word><space><hyphenminus><hyphenminus><space><word><space> yields an en dash.

That this has been true for some 3 or 4 decades makes me doubt all the comments that em dashes are a "tell" of LLM authorship. On the other hand, I guess when we confine this possibility to web content, I can see how people haven't used Office for web authoring lately, and whatever they do use (like web-based content management systems) don't tend to have this feature.

> Typing <word><space><hyphenminus><hyphenminus><space><word><space> yields an en dash.

More importantly, typing just a single hyphen minus in this constellation triggers the autoreplace, too. (Typing the double hyphen is only necessary without spaces in order to distinguish between an intentional hyphen and an em dash.)

Good point. Either way, it's kind of peculiar that getting an en dash in this manner demands flanking the hyphen(s) with spaces, and those spaces persist after replacement, when the typical usage of an en dash specifically doesn't demand spaces.

From TFA:

> August 1–August 31

From a top comment:

> Boston–San Francisco flight, 10–20 years

To achieve this using the replacement feature we're talking about would take something like <word><space><hyphenminus><space><word><space><alt+leftarrow><bksp><leftarrow><bksp><alt+rightarrow> which is ridiculous.

In professional typesetting, like a book, I sometimes see spaces flanking an em dash, however.

I can't get this to work in Powerpoint. It's funny, I clicked on this thread because I was struggling with trying to make an "emdash" in Powerpoint yesterday and couldn't find the correct search term for the "long hyphen" that I was looking for.

Works fine for me on PowerPoint for Mac, oddly enough. Unrelatedly, Mac also allows easy (non-alt-code) keyboard entry: option-hyphen yields an en dash, while option-shift-hyphen yields an em dash.

Turns into different things (like a bulleted list) in different situations in Word, though.

Seems like you're correct. Interesting!

That's one of my favorite features of macOS keyboard layouts, but it's so close to one of my least favorite ones – option + space inserting a non-breaking space.

I almost never want that, and when typing "space, en dash, space", it happens quite easily and is usually impossible to tell visually.

You always want a non-breaking space before a dash.

How so? Wouldn't this prevent line breaks around dashes bracketing parenthetical statements? That's the opposite of what I want!

Line starting with a dash can be mistaken for dialogue or dashed list, which is not what you want.

In any case: non-breaking space (or otherwise suppressed linebreak, if you don’t use a space) is the rule.

Works here on Linux too, so not just Macs.