I found another way to set Vim as the default text editor in Ubuntu but I would like to know why this tutorial is not working for me:

https://www.a2hosting.com/kb/developer-corner/linux/setting-the-default-text-editor-in-linux

Here's what I did:

I edited ~/.bashrc by adding these 2 lines:

export EDITOR='vi'

export VISUAL='vi'

Then I typed the command:

source .bashrc

I also tried to log out of my account and then log back in but it's still not working.

When I try to open the /etc/sudoers file it opens with Nano text editor instead of Vim.