Git - How to auto push changes in a directory to another branch

Question

Complete question rewrite

So I thought I was explaining this question very simply and direct but it seems I oversimplified to much, so here is a

Answer 1

What's the problem with the hook script you wrote ? What were the contents of the branch gh-pages when you created it?

I had created an empty branch gh-pages with below command:

git checkout --orphan gh-pages
git rm -rf .
touch README.txt
git add README.txt
git commit -m "Initial commit"
git push -u origin gh-pages

Then I ran below script as a part of post-receive hook and it worked for me.

#!/bin/bash
branch=`git rev-parse --abbrev-ref HEAD` 
if [ "master" == "$branch" ]; then
    git fetch && git checkout gh-pages
    git checkout master -- gh-pages
    git add -A
    git commit -m "Updating project website from 'master' branch."
    git push -u origin gh-pages
fi
done

Answer 2

You really don't need this complex approach.

Simply add your own repo as a submodule (of itself!), submodule following the gh-pages branch (since a submodule can follow the latest commit of a branch)!

git checkout master
git rm -r gh-pages # save your data first
git submodule add -b gh-pages -- /remote/url/of/your/own/repo
git commit -m "ADd gh-pages branch as submodule"
git push

That way, you can change files either in your main branch, or in the gh-pages folder (which is actually a submodule)

Whenever you are making changes in gh-pages folder, don't forget to commit there, and in the main folder of your repo in order to record the new gitlink (special entry in the index) reprsenting the new SHA1 of the gh-pages submodule.

cd myrepo/gh-pages
# modify files
git add .
git commit -m "modify gh-pages files"
cd .. # back to myrepo folder
git add gh-pages
git commit -m "record gh-pages new SHA1"
git push

With git 2.7+, you can set:

cd /path/to/main/repo
git config push.recurseSubmodules on-demand

Then a single git push from your main repo will also push the gh-pages submodule to the gh-pages branch.

Later, a single git clone would clone both your main repo and its gh-pages branch (in the gh-pages submodule folder).

That way, you always have both content visible.

And you don't need a complex "synchronization/copy" mechanism.

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Update August 2016: Simpler GitHub Pages publishing now allows to keep your page files in a subfolder of the same branch (no more gh-pages needed):

You don't need the submodule approach anymore, since your pagers can be in a subfolder within the same branch.