This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.
# IO.close (from ruby core) --- ios.close -> nil --- Closes *ios* and flushes any pending writes to the operating system. The stream is unavailable for any further data operations; an IOError is raised if such an attempt is made. I/O streams are automatically closed when they are claimed by the garbage collector. If *ios* is opened by IO.popen, #close sets `$?`. Calling this method on closed IO object is just ignored since Ruby 2.3.
This is MURDOC! A Ruby documentation browser inspired by Smalltalk-80. It allows you to learn about Ruby by browsing through its class hierarchies, and see any of its methods.