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rstrip! 

        # String.rstrip!

(from ruby core)
---
    str.rstrip!   -> self or nil

---

Removes trailing whitespace from the receiver. Returns the altered
receiver, or `nil` if no change was made. See also String#lstrip! and
String#strip!.

Refer to String#strip for the definition of whitespace.

    "  hello  ".rstrip!  #=> "  hello"
    "  hello".rstrip!    #=> nil
    "hello".rstrip!      #=> nil

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.