Dir

From RubySpec

From Programming Ruby 1st edition "Objects of class Dir are directory streams representing directories in the underlying file system. They provide a variety of ways to list directories and their contents."

Examples from Programming Ruby 1st edition(these are just conceptual examples, the actual files will depend on what files one has stored).

Dir["config.?"]  	->  	["config.h"]
Dir["*.[a-z][a-z]"] 	-> 	["main.rb"]
Dir["*.[^r]*"] 	-> 	["config.h"]
Dir["*.{rb,h}"] 	-> 	["main.rb", "config.h"]
Dir["*"] 	        -> 	["config.h", "main.rb"]