How do I configure Vim's built-in auto-completion?

Explanation

The completeopt option controls the behavior of the completion popup menu. Proper configuration makes <C-n> and <C-p> completion more user-friendly.

How it works

• menu shows a popup menu with matches
• menuone shows the menu even with a single match
• noselect does not auto-select the first item
• noinsert does not auto-insert text

Example

set completeopt=menu,menuone,noselect

Now <C-n> in insert mode shows a popup without auto-inserting.

Tips

• <C-n> triggers keyword completion
• <C-x><C-f> completes file paths
• <C-x><C-l> completes whole lines
• <C-x><C-o> triggers omni completion
• <C-y> accepts the selected completion
• <C-e> cancels the completion menu