Persistent undo and repeat

Like any editor, Vim keeps track of every operation. Press u to undo a last operation, and Ctrl + r to redo it.

Vim also allows you to persist undo history between sessions, which is great if you want to undo (or remember) something you've done a few days ago!

You can enable persistent undo by adding the following line to your .vimrc:

set undofile

However, this will litter your system with an undo file for each file you're editing. You can consolidate the undo files in a single directory, as seen in the following example:

" Set up persistent undo across all files.
set undofile
if !isdirectory("$HOME/.vim/undodir")
  call mkdir("$HOME/.vim/undodir", "p")
endif
set undodir="$HOME/.vim/undodir"

Now, you'll be able to undo and redo your changes across sessions.