How do I duplicate a whole line in Emacs?

Ray picture Ray · Sep 18, 2008 · Viewed 73.3k times · Source

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 number of commands to perform this in Emacs?

Answer

Chris Conway picture Chris Conway · Sep 18, 2008

I use

C-a C-SPACE C-n M-w C-y

which breaks down to

  • C-a: move cursor to start of line
  • C-SPACE: begin a selection ("set mark")
  • C-n: move cursor to next line
  • M-w: copy region
  • C-y: paste ("yank")

The aforementioned

C-a C-k C-k C-y C-y

amounts to the same thing (TMTOWTDI)

  • C-a: move cursor to start of line
  • C-k: cut ("kill") the line
  • C-k: cut the newline
  • C-y: paste ("yank") (we're back at square one)
  • C-y: paste again (now we've got two copies of the line)

These are both embarrassingly verbose compared to C-d in your editor, but in Emacs there's always a customization. C-d is bound to delete-char by default, so how about C-c C-d? Just add the following to your .emacs:

(global-set-key "\C-c\C-d" "\C-a\C- \C-n\M-w\C-y")

(@Nathan's elisp version is probably preferable, because it won't break if any of the key bindings are changed.)

Beware: some Emacs modes may reclaim C-c C-d to do something else.