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Vim has been my go-to editor for the last 1.5 years, yet I am still learning something new. Recently I sought to learn about the vim's dot (.) command.

Dot command is like a mini macro. Is repeats the last change made. If used correctly, it can save us time doing repetitive tasks.

I am also curious how you guys use dot command - feel free to comment below!

How does it work?

If you see the help section in vim (:h .), you'll see:

Repeat last change, with count replaced with [count]...

I immediately thought, "what does vim mean by 'change'?"

After some reading and experimenting, I concluded change means any act of updating, adding, or subtracting the content of a file. Moving around does not count as a change. Let's see if that is true by some application.

Example 1: Adding ; to the end of each line

Here is an example (source). Let's say we want to add ; at the end of each line, this can be done with the help of .:

Roses are Red
Violets are Blue
Unexpected '{'
On line 32

Assume we are starting on top left where 'R' is. We start with A ; <esc> j.

1. A jumps to end of line and enters insert mode.
2. ; adds ";", back to normal mode, then go down.

Cool, that whole (A ; <esc> j) was one change, right? No. If we do . . ., we end up with

Roses are Red;
Violets are Blue;;; <-- what happened?
Unexpected '{'
On line 32

This is because vim does not count j as part of change. Change excludes motions. In this case, vim consider a change to be A ; <esc>. We need to do A ; <esc> j . j . j .. Dot, down, dot, down, dot, down.

Example 2: Deleting specific word, but not all

For example, suppose our poem says this instead:

Roses are Red Blue
Violets are Blue
Unexpected Blue '{'
On line Blue 32

We need to delete Blues except the one on line two. We can very quickly do it using dot command.

/ Blue c i w <backspace> <esc> deletes first Blue. Then n n . n .

This time, our change consist of:

1. Delete the entire word Blue and entering insert mode (c i w)
2. Backspace while in insert mode
3. Exit

I am starting to see a pattern here. / Blue and n are not considered change by vim, but c i w <Backspace> <esc> does.

Let's do another example:

Example 3: Adding ( at the beginning on each line

Another one, suppose you have:

One)
Two)
Three)

We are adding ( at the start of each word. You can do I ( <esc> to apply the change to the first, then j . j .. Change here is I ( <esc>.

Comparing what 'changed'

Let's compare all of the repeatable changes from the past few examples:

1. A ; <esc>
2. c i w <Backspace> <Esc>
3. I ( <esc>

Do you see a pattern? They all start with commands that put you into insert mode (c, A, and I are all command that results in entering Insert mode) and end with <esc>.

Another one I didn't mention was delete commands like dd. I can delete lines repeatedly by dd . . . .. Although dd does not enter insert mode, vim considers it as a change because it deletes an entire line. Remember, anything that adds, removes, or updates text is considered as change by vim.

Application

Above are some application of dot commands. It can save us a few keystrokes - a few keystrokes saved is time gained. Next time we are doing repetitive task, see if you can repeat it with the dot command.

Thanks for reading! I really appreciate you making it this far. Happy hacking!

Resources:

• Practical Vim
• Why the dot (.) command is so useful in VIM?

Discuss

I am interested to learn how other devs take advantage of the dot command. What other ways do you think dot commands can be used?