Bind C-e C-j and C-a C-o TAB to single key, aka insert and jump to newline

Question

C-e C-j will insert a newline below and jump to it indented. C-a C-o TAB will insert a newline above and jump to it indented.

Is there a single bind to these or where/how should I bind these commands?

Answer 1

You can always check what function some keys are bound to using C-h k. For example, if we type C-h k C-e, we see that it is bound to (move-end-of-line ARG); similarly, C-j is bound to (newline-and-indent).

In this case, it turns out that C-e C-j is a sequence of two commands rather than a single thing. (The same with C-a C-o TAB.) To bind this to a single key, we first have to wrap it in a function. You can define this function in your .emacs file:

(defun my-newline-below ()
  "Insert a newline below and jump to it indented."
  (interactive)
  (move-end-of-line nil)
  (newline-and-indent))

All this function does is run the two commands we found. The string on top is just some documentation, and (interactive) is needed so that you can bind it to a key (or call it directly from M-x). move-end-of-line takes an argument, so we just pass in nil to get the default behavior. Happily, the output of C-h k tells us we can do this, so we don't have to guess what ARG is for.

Now we can just globally set this to some key:

(global-set-key (kbd "C-M-j") 'my-newline-below)

And voilà: the first command you wanted, bound to C-M-j. Now you can do the second one the same way, which is a great exercise to learn how to define your own custom commands like this.