TopolearnThe dot command turns one careful edit into many, and undo makes experimenting safe.
u undoes the last change and Ctrl-r redoes it. A change is one Normal-mode command, or everything you typed in one visit to Insert mode, so ihello world<Esc> undoes in one step.
The dot command . repeats the last change. This is the single most useful key in Vim once you learn to make your changes repeatable:
A;<Esc>thenj.j.adds semicolons to the next lines.cwfoo<Esc>thenn.changes the next search match tofootoo.ddthen...deletes three more lines.
The trick is to compose a change so it does not depend on where the cursor happens to be. A works anywhere on the line, $a is two commands and only the a part repeats. Using ciw (change inner word, from the text objects lesson) instead of cw repeats correctly even when the cursor is mid-word.
Vim also keeps a full undo tree, not just a stack: if you undo and then make a new change, the old branch is not lost. g- and g+ move back and forward through all states by time, and :earlier 5m rewinds the buffer to how it was five minutes ago. With set undofile in your config, undo history even survives closing the file.
Example
A;<Esc> " append ';' to this line
j. " move down, repeat: ';' added again
j. " and again
u " undo the last ';'
Ctrl-r " redo it
:earlier 2m " restore the buffer as it was 2 minutes ago
:later 1m " move forward in time againRemember
- u = undo, Ctrl-r = redo, . = repeat last change
- Design edits so they repeat well: A over $a, ciw over cw
- :earlier / :later travel the undo tree by time
Watch out for
- Moving the cursor inside Insert mode with arrow keys splits the change, so . only repeats the last part.