Setting up Ruby on macOs
System Ruby
macOx / os x ship with a version of Ruby, but that version is called system Ruby.
It is located in /usr/bin/ruby.
If you run which ruby and see /usr/bin/ruby then you are still using ‘System Ruby’.
This will cause the issues like:
ERROR: While executing gem ... (Gem::FilePermissionError)
You don't have write permissions for the /Library/Ruby/Gems/2.3.0 directory.
If you need to use sudo to run or install a gem, then you are likely using ‘System Ruby’. You do not want to do that.
Ruby Version Manager (RVM)
Ruby Version Manager, often abbreviated as RVM, is a software platform for unix-like operating systems designed to manage multiple installations of Ruby on the same device.
RVM can be used to change between the ‘System Ruby’ and any other Ruby Versions.
Installation
GPG
In order to install RVM we’ll need gpg, which is the key manager that RVM uses.
brew install gnupg
Once GPG is installed, use it to get the the keys as described on the RVM website:
RVM
\curl -sSL https://get.rvm.io | bash -s stable --ruby
If this command gives you trouble, check for changes on the RVM Website
To start RVM
source /Users/robin/.rvm/scripts/rvm
To confirm that RVM is managing your Ruby versions:
which ruby
Should output
/Users/your-name/.rvm/rubies/ruby-2.7.0/bin/ruby
Using RVM
- List installed versions
rvm list - Change to another version
rvm use - To list the gems that are installed in the current Ruby version
gem env