Let's check to see if Ruby on Rails is present with the list command.


$ gem list rails


$ gem install rails --include-dependencies

1.	RubyGems is a package utility for Ruby
2.	getting help on how to issue RubyGems commands:
3.	get help on what commands are available (some output truncated).
4.	help on examples (some output truncated).
5.	gem help env
6.	Show everything on the RubyGems environment with this command:
7.	show the RubyGems installation directory:
8.	You can check what dependencies a gem has with the dependency command:
9.	To select dependencies as you install a package, skip the --include-dependencies option
10.	To update all the gems on your system with all the current versions, use the update command.
11.	To uninstall a package with the uninstall command:

Let's check to see if Ruby on Rails is present with the list command. : RubyGems « Language Basics « Ruby