Kinda hard to encode it in /etc/passwd, which separates entries with newlines and fields of an entry with colons.

Of course, you can activate some alternative user database in /etc/nsswitch.conf and then you can have your usernames with newlines in them, but at least half of the tools on your system that process usernames will take that personally…

ps outputs a newline after every entry. What are you trying to accomplish?

Do you have a username that contains a newline character? If so… why?!

Given that Mac keybindings for “common special functions” (Open/Save/Cut/Copy/Paste/Find/etc.) use Command instead of Ctrl, leaving Ctrl effectively unused unless in combination with Command, this argument doesn’t hold much water.

Sure, some Emacs fan at Apple decided to add Emacs shortcuts to Cocoa controls, but that was a pretty arbitrary decision since people coming from Mac OS 9 didn’t use the Ctrl key, well, ever.