For vi-heads: ":" The key combo that puts you into command mode. M is "meta", which is Alt on PC or Cmd on Mac.
These are all conventions and you can change them, but I'm used to Meta = Opt and Super = Cmd on macOS.
Does that interfere with your being able to use Opt for typing key combos to produce Unicode codepoints that aren't usually found on a "standard" keyboard for your country? E.g., accented characters not found in your country's majority language, Greek letters when you don't have a Greek keyboard, mathematical symbols, and so on? It's been a couple decades since I owned a Mac, and I love Linux's Compose key feature, but I remember that Option+key shortcuts were really good for typing a wide variety of commonly-used Unicode codepoints. How does setting Meta = Opt work with that for you?
It does, yes. It's a reasonable trade-off for me becaues it's rare that I need to do that and if I do, I use [digraph]s in (neo)vim. The alternatives are usually more disruptive for me, (using Cmd as Meta shadows way more commonly used OS-level shortcuts, using Esc as Meta shadows Escape in Vim, and other TUIs).
[digraph]: https://neovim.io/doc/user/digraph/
That is incorrect. In vi and vim, "ESC" is the key that puts you into command mode (from insert mode). Command mode is the full-screen visual mode where you enter commands by a sequence of keypresses.
":" is the key which issues "ex" commands. vi and ex are two different modes of the same editor. Any command which begins with a colon is an ex command, not a vi command, not done in "Command Mode".
True. ":" is the rough equivalent to M-x, though.
Also worth mentioning is Q , which puts you in ex mode, essentially just ":" prompts one after the other until you exit or issue a "vi" command to go (back) to visual mode.
And then there's open mode, but vim doesn't implement that.
That is what people use for the Alt key. I mean, I use Emacs daily, and I (mostly) like it. But the terminology *) is really fucked up inside Emacs.
Almost no one realizes that perhaps since 35 years no keyboard in mass-use had an "Meta" key. And if the "e" people now still keep that weird name, then they aren't similarly frozen in the state of time as the Emacs community.
1) There's more. Lisp still let bleed assembler instructions that no CPU used in the last 40 years, like CDR and CAR. That's if like e.g. JavaScript would have a cmpxchg() function.
also 1) Or it uses "window" in a very different sense.
and also 1) and even when the term is what you expect, they -- in best english tradition! -- can't normalize on one writing. You can e.g. find both "assoc" and "assq" in use.
So if you want an extremely powerful editor construction kit with an extremely weird nomenclature of parts of it, then chose Emacs.