Magic $-prefixed variables in Ruby; is there a complete reference somewhere?

Question

I've seen magic variables like this used in Ruby. $_ $' $0

Is there a complete reference for what all of them mean and how they are set?

Answer 1

They are called "global variables" (complete list at the bottom of the page): http://www.rubyist.net/~slagell/ruby/globalvars.html

Answer 2

Their name is global variables. There are several different references.

You can get a full list by calling the method Kernel#global_variables

puts global_variables

Ruby also includes in the standard library a file called English.rb which provides an in-depth explanation of several global variables.

Finally, here's an other reference.