Yesterday, I decided I wanted to edit a bunch of Jekyll posts. Specifically, I wanted to move the title field in each post’s YAML front matter to the bottom. Instead of having to manually edit a few hundred files, I finally remembered to use Vim macros.

In Vim, a macro is a recording of a number of commands. Once you’ve recorded a macro, you can replay it any number of times. So the idea for this task was to record a macro that could I could replay, that would locate the title line and move it to the bottom of the post’s YAML front matter.

To illustrate how this works, let’s take a look at this post’s YAML front matter:

---
layout: default
title: "Fun With Jekyll Posts and Vim Macros"
date: "Tue Feb 05 19:57:11 -0500 2013"
---

...

To rearrange these lines as desired, you can use these commands in Vim:

gg
/title<cr>
dd
/---<cr>
P
  • gg: Move to line 1
  • /^title:<cr>: Move to the first line starting with “title:”
  • dd: Delete that line to the default register
  • /^---<cr>: Move to the next line starting with “—”
  • P: Paste the contents of the default register above the current line

This gives you the proper sorting, but the process needs to be repeated in each file:

---
layout: default
date: "Tue Feb 05 19:57:11 -0500 2013"
title: "Fun With Jekyll Posts and Vim Macros"
---

...

To use this as a macro, you just need to record it with q. Expanding on the commands above:

qq
gg
/title<cr>
dd
/---<cr>
P
:w
q
  • qq: Start recording a new macro named “q”
  • gg: Move to line 1
  • /^title:<cr>: Move to the first line starting with “title:”
  • dd: Delete that line to the default register
  • /^---<cr>: Move to the next line starting with “—”
  • P: Paste the contents of the default register above the current line
  • :w: Write the file
  • q: End recording

You now have a macro that can be played back with @q. This is much quicker, but you still need to edit each file and manually press @q. To handle this for multiple files you can use :args and :argdo.

:args _posts/*.markdown
:argdo normal @q
  • :args _posts/*.markdown: Set the files to target
  • :argdo normal @q: Run normal @q for each file. This is the same manually running @q in the file.

After you’re done, all the files will be updated. Huzzah, macros!