rubygems.rb:334:in `bin_path’: can’t find executable rails for rails-3.2.1 (Gem::Exception)

After updating my MacOS I got this message:
rails -v /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/rubygems.rb:334:in `bin_path': can't find executable rails for rails-3.2.1 (Gem::Exception) from /usr/bin/rails:19

$ sudo gem update rails Updating installed gems Updating coffee-rails Successfully installed coffee-rails-3.2.2 Successfully installed activesupport-3.2.8 Successfully installed activemodel-3.2.8 Successfully installed rack-cache-1.2 Successfully installed journey-1.0.4 Successfully installed sprockets-2.1.3 Successfully installed actionpack-3.2.8 Updating jquery-rails Successfully installed jquery-rails-2.1.1 Updating rails Successfully installed activerecord-3.2.8 Successfully installed activeresource-3.2.8 Successfully installed mail-2.4.4 Successfully installed actionmailer-3.2.8 Successfully installed railties-3.2.8 Successfully installed rails-3.2.8 Updating sass-rails Successfully installed sass-rails-3.2.5 Gems updated: coffee-rails, activesupport, activemodel, rack-cache, journey, sprockets, actionpack, jquery-rails, activerecord, activeresource, mail, actionmailer, railties, rails, sass-rails Installing ri documentation for coffee-rails-3.2.2... Installing ri documentation for activesupport-3.2.8... Installing ri documentation for activemodel-3.2.8... Installing ri documentation for rack-cache-1.2... Installing ri documentation for journey-1.0.4... Installing ri documentation for sprockets-2.1.3... Installing ri documentation for actionpack-3.2.8... Installing ri documentation for jquery-rails-2.1.1... Installing ri documentation for activerecord-3.2.8... Installing ri documentation for activeresource-3.2.8... Installing ri documentation for mail-2.4.4... Installing ri documentation for actionmailer-3.2.8... Installing ri documentation for railties-3.2.8... Installing ri documentation for rails-3.2.8... Installing ri documentation for sass-rails-3.2.5... Installing RDoc documentation for coffee-rails-3.2.2... Installing RDoc documentation for activesupport-3.2.8... Installing RDoc documentation for activemodel-3.2.8... Installing RDoc documentation for rack-cache-1.2... Installing RDoc documentation for journey-1.0.4... Installing RDoc documentation for sprockets-2.1.3... Installing RDoc documentation for actionpack-3.2.8... Installing RDoc documentation for jquery-rails-2.1.1... Installing RDoc documentation for activerecord-3.2.8... Installing RDoc documentation for activeresource-3.2.8... Installing RDoc documentation for mail-2.4.4... Installing RDoc documentation for actionmailer-3.2.8... Installing RDoc documentation for railties-3.2.8... Installing RDoc documentation for rails-3.2.8... Installing RDoc documentation for sass-rails-3.2.5...

$rails -v Rails 3.2.8
So it all runs fine again.