Ruby: Finding most recently modified file

What's an idiomatic way to find the most recently modified file within a director开发者_Go百科y?

Dir.glob("*").max_by {|f| File.mtime(f)}

Dir["*"].sort { |a,b| File.mtime(a) <=> File.mtime(b) }.last

This is not recursive.

I'm not sure if there really is an idiom for this. I would do

Dir["*"].sort_by { |file_name| File.stat(file_name).mtime }

Edit

Seeing how three people gave more or less the same answer at the same time. This must be it.