(defun scrollup-n (&optional n)
  "Scroll the text up n (default 1) lines."
  (interactive "p")
  (scroll-up (or n 1))
)
(global-set-key [S-down] 'scrollup-n)

(defun scrolldown-n (&optional n)
  "Scroll the text down n (default 1) lines."
  (interactive "p")
  (scroll-down (or n 1))
)
(global-set-key [S-up] 'scrolldown-n)

(defun scrollup-6n (&optional n)
  "Scroll the text up 6n (default 6) lines."
  (interactive "p")
  (scroll-up (* 6 (or n 1)))
)
(global-set-key [C-S-down] 'scrollup-6n)

(defun scrolldown-6n (&optional n)
  "Scroll the text down 6n (default 6) lines."
  (interactive "p")
  (scroll-down (* 6 (or n 1)))
)
(global-set-key [C-S-up] 'scrolldown-6n)

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(defun screen-top ()
  "Move the point to the top of the screen."
  (interactive)
  (move-to-window-line 0)
)
(global-set-key [C-left] 'screen-top)

(defun screen-bottom ()
  "Move the point to the bottom of the screen."
  (interactive)
  (move-to-window-line -1)
)
(global-set-key [C-right] 'screen-bottom)

(defun scroll-to-top (&optional n)
  "Scroll the current line to the top of the window"
  (interactive "P")
  (recenter (if n (prefix-numeric-value n) 0)))
(global-set-key [C-S-right] 'scroll-to-top)

(defun scroll-to-bottom (&optional n)
  "Scroll the current line to the bottom of the window.
If given a numerical arg, leave point that many lines from the bottom."
  (interactive "p")
  (recenter (- (or n 1))))
(global-set-key [C-S-left] 'scroll-to-bottom)

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(defun 4-column ()
  "Disply the current buffer in 3 columns with follow-mode"
  (interactive)
  (follow-mode 1)
  (delete-other-windows)
  (split-window-horizontally) (split-window-horizontally)
  (split-window-horizontally)
  (balance-windows))
(global-set-key "\C-c4" '4-column)

(defun 3-column ()
  "Disply the current buffer in 3 columns with follow-mode"
  (interactive)
  (follow-mode 1)
  (delete-other-windows)
  (split-window-horizontally) (split-window-horizontally)
  (balance-windows))
(global-set-key "\C-c3" '3-column)

(defun 2-column ()
  "Disply the current buffer in 2 columns with follow-mode"
  (interactive)
  (follow-mode 1)
  (delete-other-windows)
  (split-window-horizontally)
  (balance-windows))
(global-set-key "\C-c2" '2-column)

(global-set-key "\C-c0" (lambda () (interactive) (message "follow-mode disabled") (follow-mode 0)))

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(defun do-vm (arg)
  "Do (vertical-motion ARG), where ARG is a number, default of 0."
  (interactive "P")
  (vertical-motion (if arg (prefix-numeric-value arg) 0)))
(global-set-key "\C-cm" 'do-vm)