Redo
What good is undo without its trusty companion redo?
You can redo in Vim using <C-r> in normal mode — that is, hold control on your keyboard and hit r.
Redo is exactly what it says on the tin — it takes you in the opposite direction to undo, toward your more recent edits.
Work through the checklist below to take a round trip through the undo history: delete a line, undo the deletion, then redo it with <C-r>.