Of course there is a way to duplicate a line in Emacs by default. Like in vi, you compose simple commands. Let's see: ; Duplicates the current line S-C-b

Of course there is a way to duplicate a line in Emacs by default. Like in vi, you compose simple commands. Let's see: ; Duplicates the current line S-C-backspace C-[y y] ; Duplicates the current line C-[a k k y y] ; Duplicates the current line C-[a SPC n w y y] ; Duplicates the current line C-[a SPC n] ESC w C-y Repeat duplicating until it looks like enough: ; Duplicate again until happy C-[y y y...] ; Duplicate again until happy C-x z z z... Duplicate 3 lines instead of 1: ; Duplicate this line and the next two C-[a u] 3 C-[k y y] Duplicate 10 times: ; Duplicate the current line 10 times C-[a k k] C-x ( C-y C-x ) C-u 10 C-x e ; Duplicate the current line 10 times C-[a SPC n w] C-x ( C-y C-x ) C-u 10 C-x e ; Duplicate the current line 10 times S-C-backspace C-x ( C-y C-x ) C-u 10 C-x e Remove duplicate lines instead: ; Select region, then M-x delete-duplicate-lines