Yes, they are duplicates. If you want to use one of them for your own purposes, I would recommend to keep the meta ones and rebind the control ones. One reason to keep the meta ones is that if you run Emacs in a terminal, most terminals don't transmit digit differently from plain Ctrl+digit, which makes Ctrl+digit bindings inaccessible. On the other hand text terminals transmit Meta+digit as Esc digit. Another reason to keep the meta bindings is that they are the same bindings that let you type Esc digit…, since the Meta (M-
) modifier is equivalent to the
Esc (ESC
) prefix.
If you really want, you can even rebind both, since the same functionality is also available by typing Ctrl+U and then digits without any modifier. So for example all of the following are equivalent and move the point 12 words to the left:
C-1 C-2 C-left
M-1 M-2 M-b
C-u 1 2 C-left
ESC 1 2 C-left
M-1 C-2 M-b
…