What's the difference between "git symbolic-ref HEAD refs/heads/gh-pages" and "git branch gh-pages"?

Question

This is the process given to create a branch for GitHub Project Pages:

cd /path/to/repo-name
git symbolic-ref HEAD refs/heads/gh-pages
rm .git/index
git clean -fdx
echo "My GitHub Page" > index.html
git add .
git commit -a -m "First pages commit"
git push origin gh-pages

It states that git symbolic-ref HEAD refs/heads/gh-pages will create a new root branch. I'm wondering what the difference between a root branch and a regular branch is.

Answer 1

A "root branch" is one without a previous history. *

If you are at master and you do git branch gh-pages, gh-pages will be basedd off master.

Here, the intention is to create a branch for github pages, which is typically not associated with the history of your repo (master and other branches) and hence the usage of git symbolic-ref

Also see here: https://stackoverflow.com/a/8815361/526535

* It is also called an orphan branch and git checkout --orphan will now do the same thing as the git symbolic-ref that was being done before

Also see my answer here: https://stackoverflow.com/a/5690048/526535