Выделить столбец в Emacs

;;; rect-mark.el --- Mark a rectangle of text with highlighting.
;;; Copyright (C) 1994, 1995 Rick Sladkey <jrs@world.std.com>
;;; http://www.emacswiki.org/elisp/rect-mark.el
;;; Support for marking a rectangle of text with highlighting.
(define-key ctl-x-map "r\C-@" 'rm-set-mark)
(define-key ctl-x-map [?r ?\C-\ ] 'rm-set-mark)
(define-key ctl-x-map "r\C-x" 'rm-exchange-point-and-mark)
(define-key ctl-x-map "r\C-w" 'rm-kill-region)
(define-key ctl-x-map "r\M-w" 'rm-kill-ring-save)
(define-key global-map [shift down-mouse-1] 'rm-mouse-drag-region)
(autoload 'rm-set-mark "rect-mark"
  "Set mark for rectangle." t)
(autoload 'rm-exchange-point-and-mark "rect-mark"
  "Exchange point and mark for rectangle." t)
(autoload 'rm-kill-region "rect-mark"
  "Kill a rectangular region and save it in the kill ring." t)
(autoload 'rm-kill-ring-save "rect-mark"
  "Copy a rectangular region to the kill ring." t)
(autoload 'rm-mouse-drag-region "rect-mark"
  "Drag out a rectangular region with the mouse." t)

Далее C-x r C-SPC :)

Type: "CTRL-h a rectangle"