Are these two vi-related `.inputrc` lines redundant?

Question

I've seen people recommend putting both of the following lines in one's .inputrc to enable vi key-mappings:

set editing-mode vi
set keymap vi

Sometimes, they are recommended separately; sometimes, they are recommended together. Gah! Are both necessary on any systems?

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As a greedy side note, if either of those are included in one's .inputrc, is it still necessary to include:

set -o vi

...in one's .bash_profile?

Answer 1

The file /etc/inputrc or ~/.inputrc controls the library readline. Readline is used by many many programs (including bash).

The second one, set -o vi controls only bash. vimrc has no effect on bash.

Answer 2

Only the first line is necessary:

set editing-mode vi

The second line defines how future manual key mappings will be applied:

set keymap vi