Ruby $!

This week I enjoyed using Ruby's built-in global variables, including $!. $! refers to the last error that was raised, and is useful in lots of different contexts such as Rake tasks.

Here it is in action:

:001 > begin; raise NameError; rescue; puts "The error we raised was #$!."; end
The error we raised was NameError.

And a list of these global variables:

https://github.com/ruby/ruby/blob/trunk/lib/English.rb

For a slightly less bare-metal implementation, require this library and utitlize the friendly names:

:001 > require 'english'
 => true
:002 > begin; raise NameError; rescue; puts "The error we raised was #$ERROR_INFO."; end
The error we raised was NameError.