jmopines/site/content/thissite/dates.md

title	date	draft	tags
How Dates Work on This Site	2026-04-03	false	hugo git workflow

Every page on this site has two dates: Created and Last Modified. Neither one is maintained by hand. Here's the full flow.

Creating a new page

New content is created via Hugo's CLI (running in Docker):

docker run --rm -v "${SITE_DIR}:/src" -w /src \
  ghcr.io/gohugoio/hugo:latest new content/thissite/my-page.md

Hugo reads the archetype template at archetypes/default.md:

+++
date = '{{ .Date }}'
draft = true
title = '{{ replace .File.ContentBaseName "-" " " | title }}'
tags = []
+++

At creation time, Hugo substitutes {{ .Date }} with the current timestamp and writes it into the new file's front matter. The result looks like:

---
date: 2026-04-03T14:30:00-04:00
draft: true
title: "My Page"
tags: []
---

That date value is baked into the file once and never changes. It represents when the page was created. Nobody edits it afterward.

How "Last Modified" works

The lastmod field is not stored in the file at all. It's resolved at build time by Hugo based on this config in hugo.toml:

enableGitInfo = true

[frontmatter]
  date = [':default']
  lastmod = [':git', ':fileModTime']

The resolution chain for lastmod:

1. :git — Hugo calls git log to find the author date of the most recent commit that touched the file. This is the primary source.
2. :fileModTime — Fallback to the filesystem modification time (useful when the file hasn't been committed yet, e.g. during local preview).

So when Hugo builds the site, it inspects the git history for each content file and injects .Lastmod into the page context. Templates can then render it with {{ .Lastmod }}.

What does git actually track?

Git records the author date on each commit. When you edit a file and commit it, that commit's date becomes the new lastmod for that file. The original date in front matter is untouched — it still reflects creation time.

commit abc123
Author: JM <jm@example.com>
Date:   Thu Apr 3 14:30:00 2026 -0400

    Fix typo in dates page

Hugo will see Apr 3 14:30:00 2026 as the lastmod for any file modified in that commit.

The full lifecycle

Step	What happens	Where the date lives
hugo new content/thissite/foo.md	Archetype stamps date	In the file's front matter
First git commit	Git records author date	In git history
Edit the file later	date in front matter unchanged	Still in front matter
git commit the edit	Git records a new author date	In git history
hugo build	Hugo reads date from front matter, lastmod from git	Injected into page context at build time

Key points

• Created date: set once by the archetype, stored in front matter, never changes.
• Last modified: not stored in the file. Resolved from git at build time. Zero maintenance.
• enableGitInfo = true is required in hugo.toml for any of the git-based date resolution to work.
• No tracking needed for lastmod — it's derived, not stored.