If you are running Linux Mint 12 as your Ruby / Rails development environment and you are planning on deploying to Heroku you will need to install Heroku’s Toolbelt in order to execute the commands necessary to create an application in their cloud as well as various other administrative commands.

Heroku provides detailed tutorials to assist you in setting up your environment but as expected they are pretty agnostic when it comes to specific Linux distributions.

For Linux Mint 12 doing the GEM install of the Toolbelt you run the following command and it executes without issue:

gem install heroku foreman

But when you attempt the login command you may get the following error:

heroku login
/rubygems/custom_require.rb:55:in `require': cannot load such file -- readline (LoadError)

I found this was due to a missing gem which is required by either the Heroku Toolbelt or Foreman gems. To correct this issue I installed the ruby readline gem with the following command:

gem install rb-readline

Once the install completed I attempted the Heroku login command again and it was successful.