Apple - How do I edit current shell command in VI

You want set -o vi (add it to your ~/.bashrc). Then, to edit the current line, just hit Esc to enter command mode.

See http://www.gnu.org/software/bash/manual/bashref.html#Readline-vi-Mode

To edit the current command in a full-screen editor, set your VISUAL environment variable to vim (I assume you want vim), then in command mode in the current comment, hit v.

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To show the mode in the prompt:

$ cat ~/.inputrc
set editing-mode vi
set show-mode-in-prompt on
set vi-ins-mode-string +
set vi-cmd-mode-string :

Your edit-and-execute-command may not be bound for vi mode. Try:

bind -m vi-insert '"\C-x\C-e": edit-and-execute-command'

To make it permanent, add that line to your ~/.inputrc file.

(via this answer; credit to @unforgettableid for the link)