How do I duplicate a whole line in Emacs?

Question

I saw this same question for VIM and it has been something that I myself wanted to know how to do for Emacs. In ReSharper I use CTRL-D for this action. What is the least num

Answer 1

When called interactively with no active region, COPY (M-w) a single line instead :

(defadvice kill-ring-save (before slick-copy activate compile)
  "When called interactively with no active region, COPY a single line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (message "Copied line")
     (list (line-beginning-position)
           (line-beginning-position 2)))))

When called interactively with no active region, KILL (C-w) a single line instead.

(defadvice kill-region (before slick-cut activate compile)
  "When called interactively with no active region, KILL a single line instead."
  (interactive
   (if mark-active (list (region-beginning) (region-end))
     (message "Killed line")
     (list (line-beginning-position)
           (line-beginning-position 2)))))

Also, on a related note:

(defun move-line-up ()
  "Move up the current line."
  (interactive)
  (transpose-lines 1)
  (forward-line -2)
  (indent-according-to-mode))

(defun move-line-down ()
  "Move down the current line."
  (interactive)
  (forward-line 1)
  (transpose-lines 1)
  (forward-line -1)
  (indent-according-to-mode))

(global-set-key [(meta shift up)]  'move-line-up)
(global-set-key [(meta shift down)]  'move-line-down)