This is kind of a dumb post.* I like to use the viper package for emacs, which mostly works just fine. I’m in the habit of using C-[ (hold-down control, press '[') instead of <escape> to back into command mode.
Sometimes I run emacs on Mac OS X (be it a Carbon port, in X11, or through a terminal). Unfortunately, various Mac-compatible emacsen interpret C-[ as Meta and not as <escape>. So instead of backing into command mode, I see "ESC-" at the bottom of the screen. I can wait forever and emacs will never parse it into an <escape>. If I try again, I see "ESC-ESC-". If I try a third time, the command completes but does nothing, except causing me to scream in agony since I'm still not in command mode.
Fortunately I found that adding a simple (setq viper-ESC-key "^[") to my ~/.viper, where '^[' is literally the <escape> character (i.e., ASCII 27)**, fixes everything (viper-ESC-key is set to "\e" by default, which is supposed to be <escape> but whatever).
And there you have it.
* ... but this took me months to figure out. I'm posting this so that maybe someone searching for "mac os x emacs meta escape viper fails" finds the help they need...
** If you're editing in emacs, type C-q C-[ to get a literal '^]‘. If you’re editing in vim, type C-k C-[ to get a literal ‘^[‘.


A Window Manager, commonly abbreviated wm, is a program that controls the way your windows appear and behave. A good wm can be likened to an operating system: it provides a necessary service, but you barely know it’s there it because it doesn’t get in the way.