Add aliases to all posts for old Hugo/Jekyll URL redirects

Start by inspecting the frontmatter in posts/2013//index.md, posts/2019//index.qmd, and posts/2020/*/index.qmd, then apply the three alias cases to the remaining posts under posts/. Skip the 2026 cherry blossoms post, preserve existing aliases, and run quarto render; done means redirect HTML files appear under _site/YYYY/MM/DD/slug/index.html for the old URLs.

Background

The site has gone through several CMS migrations:

• Jekyll (2013–2014): URL pattern /YYYY/MM/DD/slug/
• Hugo/blogdown (2015–2020): same URL pattern /YYYY/MM/DD/slug/
• Quarto (current): URL pattern /posts/YYYY/YYYY-MM-DD-slug/

External sites link to the old URL format. For example, a Posit blog post links to:
https://chendaniely.github.io/2019/08/28/r-or-python-which-one-to-learn-first/

The current URL for that post is:
https://chendaniely.github.io/posts/2019/2019-08-28-r-or-python-which-one-to-learn-first/

Solution

Quarto supports an aliases: field in post frontmatter that generates HTML redirect pages at the listed paths. Add the old-style URL as an alias to every post.

Example — add to posts/2019/2019-08-28-r-or-python-which-one-to-learn-first/index.qmd:

aliases:
  - /2019/08/28/r-or-python-which-one-to-learn-first/

Implementation

All 62 posts (2013–2020 + 2026) live under posts/ as index.md or index.qmd.
The old alias URL is always /YYYY/MM/DD/slug/ and can be derived in one of three ways depending on what frontmatter the post has:

Case 1 — Has permalink: (2 posts, both in 2013)

Use the permalink: value directly as the alias.

# existing
permalink: /2013/02/21/setting-up-virtualbox/
# add
aliases:
  - /2013/02/21/setting-up-virtualbox/

Files: posts/2013/*/index.md

Case 2 — Has slug: + date: (11 posts, 2019–2020 Rmd→qmd conversions)

Derive the alias from date: 'YYYY-MM-DD' + slug: some-slug-value:
→ alias = /YYYY/MM/DD/some-slug-value/

Some slugs are empty (slug: []) — for those, derive the slug from the folder name
(strip the YYYY-MM-DD- prefix from the folder name).

Files: posts/2019/*/index.qmd, posts/2020/*/index.qmd

Case 3 — Has neither permalink: nor slug: (48 posts, 2014–2018)

Derive alias entirely from the folder name.
Folder: posts/YYYY/YYYY-MM-DD-some-slug/
→ Parse date as YYYY/MM/DD, slug as everything after YYYY-MM-DD-
→ alias = /YYYY/MM/DD/some-slug/

Script approach

A Python or R script can handle all three cases:

1. Walk every posts/YYYY/*/index.* file
2. Parse the YAML frontmatter
3. Determine the alias URL via the case logic above
4. Inject aliases: [/YYYY/MM/DD/slug/] into the frontmatter if not already present
5. Write back the file

The PyYAML or yaml R package can parse/write the frontmatter.
Alternatively a sed/awk script can do it since the frontmatter is always at the top between --- delimiters.

Notes

• The 2026 cherry blossoms post (posts/2026/) has no old URL — skip it
• Some 2016–2018 posts use underscores in folder names (e.g. 2016-08-31-a_simple_model_of_global_cascades_on_random_networks) — the old Hugo URL used the same underscore slug, so the derived alias should match
• After adding aliases, run quarto render to confirm the redirect HTML files are generated under _site/YYYY/MM/DD/slug/index.html