It’s really simple to set it on user side settings:

Set the following in your ~/.inputrc:

set editing-mode vi
set keymap vi

and this in your ~/.bashrc:

set -o vi

You can also do the same as system default adding the same lines on /etc/inputrc and /etc/bashrc

Now you can edit your command line with Vi editing command:

Qui parlerò di un pò di tutto, ma in particolare di informatica.
Sono Italiano quindi spesso troverai articoli scritti sia in Inglese che in Italiano.
Dai un’occhiata alle categorie English e Italiano.

Buon divertimento!

Here I will speak about everything, above all computer related subject.
I’m Italian so you will often find articles on both languages, Italian and English, take a look under English and Italian categories.

Have fun!
Antenore Gatta