Zap Gremlins

When copying text into Vim from Microsoft applications, such as Outlook or Word, oftentimes at the end of every line will be a ^M character. It looks something like this in my text editor:

This is an example of gremlins^M
appearing at the end of every^M
line. Who likes to look at such^M
atrocities? Certainly not me.^M

In the Unix world, we end lines with a single newline, but in the Windows world, the end-of-line is marked by a paring of a newline with a carriage return. The carriage return character shows up in Vim as ^M.

I call them "gremlins." They are mostly harmless but annoying, since they make my text a bit uglier. More seriously, they can also cause issues with other applications.

What to do, especially if we are happily living in the Unix world? Destroy them all with a single command, of course.

The command

Here is the Ex command I use to zap gremlins from my document, in all its cryptic, oops-my-cat-typed-this glory:

maHmb:%s/<C-V><CR>//ge<CR>'bzt'a

Don't worry, there's a shortcut for that, which I'll get to later.

The vomit of seemingly random characters looks more horrifying than it actually is. Let's break it down. It's actually a series of individual Ex commands, all run together as one big "command."

The breakdown

1. ma creates a new mark at the cursor's current position, saving it as mark a¹.
2. H moves the cursor to the top of the screen.
3. mb creates a new mark at the cursor's current position, saving it as mark b. This is so that we can have a reference to the original scroll position¹.
4. :%s/<C-V><CR>//ge<CR> is a global find-and-replace command, which deletes all ^M characters in the current buffer (to find the gremlins, we search for <C-V><CR>).
5. 'b moves the cursor to mark b, the previous top of screen¹.
6. zt forces a redraw, to restore the original scroll position.
7. 'a moves the cursor back to mark a, to restore the starting cursor position¹.

#4 is the key command in the sequence; everything else going on is just bookkeeping to maintain a consistent cursor and scroll position afterwards.

The shortcut

In our Vim configuration, we define a new key binding (shortcut) and paste that gnarly command after it.

" zap gremlins (the Windows ^M)
nnoremap <Leader>mm maHmb:%s/<C-V><CR>//ge<CR>'bzt'a

In my case, my Vim leader key is a comma, which means that simply typing ,mm while in normal mode will run our compound Ex command to zap all gremlins in the current buffer.