How powerful Pathname is! Unfortunately I did not know. Have you ever been annoyed which class to use, File, FileTest, Dir or Find? Use Pathname, instead. That’s all (on UNIX platforms). The Pathname class, included in the Ruby 1.8 standard libraries, represents paths of directories and files, and is a facade to File, FileTest, Dir and Find.

You can see some examples in the header lines of the source:

   require 'pathname'
   p = Pathname.new("/usr/bin/ruby")
   size = p.size              # 27662
   isdir = p.directory?       # false
   dir  = p.dirname           # Pathname:/usr/bin
   base = p.basename          # Pathname:ruby
   dir, base = p.split        # [Pathname:/usr/bin, Pathname:ruby]
   data = p.read
   p.open { |f| _ } 
   p.each_line { |line| _ }

That means

   p = "/usr/bin/ruby" 
   size = File.size(p)        # 27662
   isdir = File.directory?(p) # false
   dir  = File.dirname(p)     # "/usr/bin" 
   base = File.basename(p)    # "ruby" 
   dir, base = File.split(p)  # ["/usr/bin", "ruby"]
   data = File.read(p)
   File.open(p) { |f| _ } 
   File.foreach(p) { |line| _ }

Pathname has exist?, file?, mkdir, rmdir, rmtree, children, find and so on as well.