I recently switched to a new computer. The switch isn’t too messy because I basically have all my data backed up, either on Google Drive or on GitHub.

One thing I wanted to make sure is that I can still update this blog, which is hosted using Octopress. But to be honest, until recently I am not really good at using git and GitHub, so it took me some time to figure out what I need to do to resume blogging with Octopress.

Logically, the key concept with Octopress is that it uses a ghost branch. All the source files for my blog is tracked NOT by the master branch, but by a ghost branch (named “source” under the Octopress framework) that is completely unrelated to the master branch in terms of git history – it’s a hanging branch that lives in a parallel world albeit in the same repo, hence the name “ghost branch.”

Another important thing with Octopress is to find out how the local blog is deployed onto GitHub Pages. This also took me a little bit to figure out. It turns out that my blog is first generated under a _deploy folder, and then that folder is synced to the master branch on the repo.

Summarizing the two paragraphs above, Octopress is organizing my blog in the following way:

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MyBlog
|--source files (tracked by ghost branch)
|--_deploy
   |--github page files (tracked by master branch)

Apparently, it is not the best practice to use a ghost branch, also not the best practice to use the master branch to track a sub-folder of the ghost branch. These are some twisted logic puzzles for the mind. But that’s how Octopress works!

Once the logic is clear, I only need to do the following three things to resume blogging:

1. Clone source from ghost branch (my ghost branch named source)

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git clone -b source https://github.com/YOURNAME/YOURNAME.github.io.git

2. Clone GitHub Page (to a sub-directory _deploy) from master branch

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cd YOURNAME.github.io
mkdir _deploy
git clone https://github.com/YOURNAME/YOURNAME.github.io.git _deploy

3. Re-install the plugins for my blog

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bundle install --path vendor/bundle

Of course, you need to have installed the Bundler to use the bundle command, and to do that on a Mac you will probably need to first install rbenv for smoothly running your blog by executing Ruby commands. In other word, you will need to set up your environment again for Octopress, which I have covered in my first blog post (in Chinese).

(Updates on 2019-11-20) Using rbenv on MacOS Catalina

After I upgraded my MacOS to 10.15 Catalina, I encountered troubles again. This time, when I do rake commands, I got the error message:

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You must use Bundler 2 or greater with this lockfile.

So I need to update the bundler to version 2 or higher.

However, when I did gem install bundler, I got permission error again – this means that gem is trying to install bundler on Mac’s default system ruby, in other words, rbenv is broken.

So I tried to reinstall rbenv :

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brew reinstall rbenv
rbenv init

and then install a custom ruby (version 2.6.5):

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rbenv install 2.6.5

However, in this last step, I constantly ran into troubles. It was a long debugging process, so I am just going to list the hurdles that I have gone through, which maybe helpful to others.

Hurdle #1: openssl overhead

rbenv keep trying to first install openssl before actually installing ruby 2.6.5, this is taking a lot of time and greatly reducing my debugging efficiency. I checked which openssl and confirmed that my system has already had openssl installed. So I need to tell rbenv to use my system’s openssl. I do this with the command:

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RUBY_CONFIGURE_OPTS=--with-openssl-dir=/opt/local CC=/usr/bin/gcc rbenv install 2.6.5

Hurdle #2: incorrect C compiler

After many fails, I finally found out in the error log that rbenv is using CC=x86_64-apple-darwin13.4.0-clang as C compiler and therefore has not been able to compile and install ruby. This can be resolved by explicitly telling rbenv to use the system compiler /usr/bin/gcc.

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CC=/usr/bin/gcc RUBY_CONFIGURE_OPTS=--with-openssl-dir=/opt/local rbenv install 2.6.5

Hurdle #3: anaconda gets in the way

After the previous two fixes, I am still unable to install ruby. This time I found the following lines in the error log:

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/anaconda3/bin/x86_64-apple-darwin13.4.0-ar: illegal option -- n
usage:  ar -d [-TLsv] archive file ...

It turns out that rbenv is using anaconda’s ar function instead of the system’s own ar. So I need to disable anaconda in my system as follows:

• Open the ~/.bash_profile file, remove/comment out any lines that have to do with anaconda/conda
• Restart terminal
• Try install ruby again:

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RUBY_CONFIGURE_OPTS=--with-openssl-dir=/opt/local rbenv install 2.6.5

Finally, I was able to install ruby on rbenv! Notice that in the last command I have removed CC=/usr/bin/gcc, because disabling anaconda also resolves the problem in Hurdle #2.

Final Steps

After installing a custom ruby, I need to first tell the system to use that version of ruby

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rbenv global 2.6.5

Then I can go back to my Octopress blog folder and install the newest bundler

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gem install bundler
bundle install

However, there is still a final small hurdle for me:

Hurdle #4: rake version

When I tried to create a new blog post via rake new_post['title'], I got the following error message:

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rake aborted!
Gem::LoadError: You have already activated rake 12.3.2, but your Gemfile requires rake 10.5.0. Prepending `bundle exec` to your command may solve this.

So I just open the Gemfile in my Octopress folder, find the line with gem 'rake', '~> 10.5', change it to gem 'rake', '~> 12.3', and then bundle install again. Now it’s all set.