This is a Ruby tree! It shows every object from the Ruby Programming Language in a tree format.

rewind 

        # IO.rewind

(from ruby core)
---
    rewind -> 0

---

Repositions the stream to its beginning, setting both the position and
the line number to zero; see [Position](#class-IO-label-Position) and
[Line Number](#class-IO-label-Line+Number):

    f = File.open('t.txt')
    f.tell     # => 0
    f.lineno   # => 0
    f.readline # => "This is line one.\n"
    f.tell     # => 19
    f.lineno   # => 1
    f.rewind   # => 0
    f.tell     # => 0
    f.lineno   # => 0

Note that this method cannot be used with streams such as pipes, ttys,
and sockets.

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.