Generating Guids in Ruby

Did you look at UUIDTools?

UUIDTools was designed to be a simple library for generating any of the various types of UUIDs (or GUIDs if you prefer to call them that). It conforms to RFC 4122 whenever possible.

How to create small, unique tokens in Ruby

>> require 'digest'
=> []
>> Digest::SHA1.hexdigest("some-random-string")[8..16]
=> "2ebe5597f"

>> SecureRandom.base64(8).gsub("/","_").gsub(/=+$/,"")
=> "AEWQyovNFo0" 

>> rand(36**8).to_s(36)
=> "uur0cj2h"

As of Ruby 1.9, uuid generation is built-in. Use the SecureRandom.uuid function.

For example:

require 'securerandom'
SecureRandom.uuid # => "96b0a57c-d9ae-453f-b56f-3b154eb10cda"

Google yields the following Ruby library:

http://raa.ruby-lang.org/project/ruby-guid/

Also, over at http://www.ruby-forum.com/topic/99262 they say you can install a gem (execute gem uuid on the command line to install it) and then do

gem 'uuid'
puts UUID.new

in your code to see a new UUID.

(Hint: I Googled for guid ruby)