I don’t need to duplicate a line often enough to make this worthwhile for me but it’s a nice solution and worth considering if you find yourself duplicating lines a lot.
Duplicate a line #emacs (global-set-key "\C-c\C-d" "\C-a\C- \C-e\M-w\C-j\C-y")
— Alex Baranosky (@Baranosky) October 13, 2014