How to change visudo editor from nano to vim? [duplicate]

When I use visudo, it always opens it with nano editor. How to change the editor to vim?

Type sudo update-alternatives --config editor

You will get a text like below.

There are 4 choices for the alternative editor (providing /usr/bin/editor).

  Selection    Path                Priority   Status
------------------------------------------------------------
* 0            /bin/nano            40        auto mode
  1            /bin/ed             -100       manual mode
  2            /bin/nano            40        manual mode
  3            /usr/bin/vim.basic   30        manual mode
  4            /usr/bin/vim.tiny    10        manual mode

Press enter to keep the current choice[*], or type selection number: 3

Find vim.basic or vim.tiny selection number. Type it and press enter. Next time when you open visudo your editor will be vim

If you want just to make your user use by default a different editor, add

export EDITOR=vim; 

in your .profile (or wherever you keep your startup environment if using a shell different from bash). Log out, log in, check that the variable is set:

[romano:~] % env | grep EDI
EDITOR=vim

and now all the programs that call an editor (and are well written) will default to vim for your user.

As noticed by @EliahKagan (thanks!) in the comment, this will not work for visudo: since you are supposed to call it using sudo, when you do

sudo visudo

the sudo command will sanitize (read: delete) most environment variables before rising privileges --- and it's a good thing it does. So the change will not percolate to visudo. To still have it working, you have to call it like:

sudo EDITOR=vim visudo

Finally, as hinted here, you can also add a line to your /etc/sudoers file near the top that reads:

Defaults editor=/usr/bin/vim 

A word of warning: when modifying your sudoers configuration, keep a terminal open with a root shell in it (with sudo -i). You never know, and you can easily get locked out of root.