I recently needed to some work in Ruby. I’m a life-long Python dev and I took some notes for anyone else in my position that is starting off and not know what tools to use:

Use RVM To Manage Ruby Distributions

RVM is Ruby’s version of Python’s virtualenv. To install it, you can execute the following commands:

gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
\curl -sSL https://get.rvm.io | bash -s stable --ruby

After it is installed, execute the following commands:

rvm reload
echo rvm_auto_reload_flag=1 >> ~/.rvmrc

Install Specific Version Of Ruby

If you want to see which version of Ruby rvm installed by default, simply execute

(getfetcher)JOSEPH-MISITI:contract josephmisiti$ rvm list
ruby-2.1.5 is not installed.
To install do: 'rvm install ruby-2.1.5'
RVM reloaded!

rvm rubies

   ruby-2.1.1 [ x86_64 ]
=* ruby-2.2.0 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

If you are working on an existing Rails app, the GemSpec file will specify a specifc version of Ruby:

Your Ruby version is 2.2.0, but your Gemfile specified 2.1.5

This is no problem, just install that specific version of ruby using rvm as follows:

(getfetcher)JOSEPH-MISITI:contract josephmisiti$ rvm install 2.1.5
Searching for binary rubies, this might take some time.
Found remote file https://rvm_io.global.ssl.fastly.net/binaries/osx/10.9/x86_64/ruby-2.1.5.tar.bz2
Checking requirements for osx.
Certificates in '/usr/local/etc/openssl/cert.pem' are already up to date.
Requirements installation successful.
ruby-2.1.5 - #configure
ruby-2.1.5 - #download
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed

Install Third Party Libraries

If you are used to Python, you are used to executing

pip install -r requirements.txt

The analogous command in Ruby is:

bundle install

Running Unit Tests

If you want to run all the unit tests in a Rails project, then you can easily do that with the following command

bundle exec foreman run rspec

Switching Between Multiple Versions of Ruby

If you need to switch between multiple Ruby installations using rvm, you can do it with the following command

rvm use 2.1.1