Beginner's Vim: Line completition

You know that when you are typing (insert mode) in Vim you can access word completition with CTRL-n (or CTRL-p), right?
This searches your buffer for words that match the pattern you have already typed in.

Well, line completition is the bigger brother of word completition.

CTRL-x CTRL-l 

The above will search you buffer (all buffer, yes) for whole lines that match the pattern!

Try it, it is pretty awesome :)