BitmapCake!

Vim by default adds two tabs when you indent something. It also messes up the whole thing if you paste a large code block with tabs into it.

Here's how you can set the tabs to 4 space width, and fix that messing up issue.

Edit your vim config file and add this at the bottom of it.

vim ~/.vimrc

and add the following.

set tabstop=4

Now save and quit. Start vim to see that it now indents your code only by a single tab :)