Often times you may need to use information from a page inside of a layout. A common usecase are javascript files particular to a page. You can use the page variable within any layout to access any data particular to a page.

Using the JavaScript example if you wanted to add scripts to a layout, the easiest thing to do would be to add the script URLs to the front_matter of the page:

title: My Page
scripts: [http://.../blah.js, http://.../bar.js]

Page content
  - page.front_matter.scripts.each do |url|
    script href=url

You may have other sections or variables on a page that you need, but this is the basics. If you need something in a page or layout, the easiest way to do this is to add it to the front-matter of the page.