I recently learned this trick since getting a new MacBook pro with the touch bar esc key. I couldn't stand the lack of travel and didn't want to remap keys, now I use the ctrl-[ combo on all keyboards out of habit
Relevant to the other conversations going on in this thread, how simple is it to re-map that ctrl-[ to work globally? I'm assuming I'd have to install something for this. I am also using a Mac and use the caps-lock-as-escape to, say, close my spotlight search bar after activating it using the command+space shortcut.
In theory at least Ctrl-[ "is" Escape and is already universal. Reason: simultaneously pressing Ctrl is the ASCII -> ASCII mathematical transformation "subtract 0x40" for keys that represent a single ASCII character. So for example Ctrl-M is 0x4d - 0x40 = 0x0a. M is 0x4d ASCII and carriage return (aka '\r', aka Enter) is 0x0d ASCII. Ctrl-M is, or at least should be, universally the same as Enter. Similarly '[' is 0x5b in ASCII, so Ctrl-'[' is 0x1b in ASCII which is the ASCII code for, you guessed it I hope, Escape. Phew that was tough on a phone.
