Returns a printable version of +self+, enclosed in double-quotes:

'hello'.dump # => "\"hello\""

Certain special characters are rendered with escapes:

'"'.dump # => "\"\\\"\""

'\\'.dump # => "\"\\\\\""

Non-printing characters are rendered with escapes:

s = ''

s << 7 # Alarm (bell).

s << 8 # Back space.

s << 9 # Horizontal tab.

s << 10 # Line feed.

s << 11 # Vertical tab.

s << 12 # Form feed.

s << 13 # Carriage return.

s # => "\a\b\t\n\v\f\r"

s.dump # => "\"\\a\\b\\t\\n\\v\\f\\r\""

If +self+ is encoded in UTF-8 and contains Unicode characters, renders Unicode

characters in Unicode escape sequence:

'тест'.dump # => "\"\\u0442\\u0435\\u0441\\u0442\""

'こんにちは'.dump # => "\"\\u3053\\u3093\\u306B\\u3061\\u306F\""

If the encoding of +self+ is not ASCII-compatible (i.e., +self.encoding.ascii_compatible?+

returns +false+), renders all ASCII-compatible bytes as ASCII characters and all

other bytes as hexadecimal. Appends <tt>.dup.force_encoding(\"encoding\")</tt>, where

<tt><encoding></tt> is +self.encoding.name+:

s = 'hello'

s.encoding # => #<Encoding:UTF-8>

s.dump # => "\"hello\""

s.encode('utf-16').dump # => "\"\\xFE\\xFF\\x00h\\x00e\\x00l\\x00l\\x00o\".dup.force_encoding(\"UTF-16\")"

s.encode('utf-16le').dump # => "\"h\\x00e\\x00l\\x00l\\x00o\\x00\".dup.force_encoding(\"UTF-16LE\")"

s = 'тест'

s.encoding # => #<Encoding:UTF-8>

s.dump # => "\"\\u0442\\u0435\\u0441\\u0442\""

s.encode('utf-16').dump # => "\"\\xFE\\xFF\\x04B\\x045\\x04A\\x04B\".dup.force_encoding(\"UTF-16\")"

s.encode('utf-16le').dump # => "\"B\\x045\\x04A\\x04B\\x04\".dup.force_encoding(\"UTF-16LE\")"

s = 'こんにちは'

s.encoding # => #<Encoding:UTF-8>

s.dump # => "\"\\u3053\\u3093\\u306B\\u3061\\u306F\""

s.encode('utf-16').dump # => "\"\\xFE\\xFF0S0\\x930k0a0o\".dup.force_encoding(\"UTF-16\")"

s.encode('utf-16le').dump # => "\"S0\\x930k0a0o0\".dup.force_encoding(\"UTF-16LE\")"

Related: see {Converting to New String}[rdoc-ref:String@Converting+to+New+String].