How to use last_modified hook

[groundedtako]

#!/usr/bin/env ruby

Check for changed posts

Jekyll::Hooks.register :posts, :post_init do |post|

commit_num = git rev-list --count HEAD "#{ post.path }"

if commit_num.to_i > 1
lastmod_date = git log -1 --pretty="%ad" --date=iso "#{ post.path }"
post.data['last_modified_at'] = lastmod_date
end

end

Hi Alexander,
You added this hook to your chirpy template. I see that all your posts now have the last_modified_at timestamp.

How is this hook used? How do I also update my posts to have this timestamp? And also how is this timestamp used on the static site?

[kungfux]

Hey @groundedtako

The last modified hook is a part of the Chirpy Starter. It checks the post history in Git to set the post.data['last_modified_at'] value. So when you make changes to the post and commit changes to Git, the post will show up as modified.

The hook does not modify or add the last_modified_at in the front matter for a post, but you can add it manually. If last_modified_at is defined in the front matter, then the hook has no effect. So if I define it manually in the front matter, I have manual control over the last modified date.

---
date: 2024-06-23 07:33:12 +0400
last_modified_at: 2024-06-23 07:33:12 +0400
---

Here is why I do this. I don't want the post to be marked as modified when I fix a typo and commit changes, but I prefer to show the post as modified when I decide to change the content, like adding or removing a paragraph. So basically, I avoid using the hook while it is still in the codebase.