Losing R-Markdown title when automating knitting

Question

I am trying to automate the creation of a bunch of Rmd files that I have been tediously knitting manually with R-Studio - using the "Knit HTML" button that is enabled when you edit an Rmd file. However if I use the knit2html command from a script, it loses the title. This is apparently explained as by design in this post:

Title not showing on R Markdown with knitr when rendering markdown file

However it does not explain how R-Studio manages to generate the title in the html files it produces - it must be possible somehow, right? I have been trying with this test.Rmd R-markdown.

---
title: "My Title"
author: "Joe Programmer"
date: "Thursday, 10 June 2015"
output: html_document
---

Just read the instructions.

And getting this when I use the Knit HTML button below

But this when I knit from the console with knit2html()

How can I get my code to work the way R-Studio does?

Answer 1

RStudio answers that here. You can see the template they use at this gist, and if you look at the markdown generation pane you'll see that eventually a wicked long pandoc call is made:

/usr/local/bin/pandoc forso.utf8.md 
  --to html 
  --from markdown+autolink_bare_uris+ascii_identifiers+tex_math_single_backslash-implicit_figures 
  --output forso.html 
  --smart 
  --email-obfuscation none 
  --self-contained 
  --standalone 
  --section-divs 
  --template /Library/Frameworks/R.framework/Versions/3.2/Resources/library/rmarkdown/rmd/h/default.html 
  --variable 'theme:bootstrap' 
  --include-in-header /var/folders/2d/r3dsy9j17lqcctq5k0hmmg040000gn/T//RtmptThd32/rmarkdown-str16cec488b85bd.html 
  --mathjax --variable 'mathjax-url:https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML' 
  --no-highlight 
  --variable highlightjs=/Library/Frameworks/R.framework/Versions/3.2/Resources/library/rmarkdown/rmd/h/highlight 

Dig into that similar output on your own system to see what else you need to pass to your own custom renderer to get the desired output.