https://www.ruby-forum.com/topic/4980931 - Gist of an irb session messing around with encodings

encoding.rb

file = File.open "acao_e_reacao_utf16_le.txt"
 => #<File:acao_e_reacao_utf16_le.txt> 

file.methods.grep /enc/
 => [:external_encoding, :internal_encoding, :set_encoding] 

file.external_encoding
 => #<Encoding:UTF-8> 

file.internal_encoding
 => nil 
 
str = file.read
 => "A\u0000\xE7\u0000\xE3\u0000o\u0000 \u0000e\u0000 \u0000R\u0000e\u0000a\u0000\xE7\u0000\xE3\u0000o\u0000" 

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

str.encode(Encoding::UTF_8)
 => "A\u0000\xE7\u0000\xE3\u0000o\u0000 \u0000e\u0000 \u0000R\u0000e\u0000a\u0000\xE7\u0000\xE3\u0000o\u0000" 

str.encode(Encoding::UTF_8, Encoding::UTF_16)
Encoding::InvalidByteSequenceError: "A\x00" on UTF-16
  from (irb):8:in `encode'
  from (irb):8
  from /home/abinoam/.rvm/rubies/ruby-2.1.1/bin/irb:11:in `<main>'

str.encode(Encoding::UTF_8, Encoding::UTF_16BE)
 => "䄀漀 攀 刀攀愀漀" 

str.encode(Encoding::UTF_8, Encoding::UTF_16LE)
 => "Ação e Reação" # THE RIGHT SOURCE ENCODING

# Another approach
# Set the encoding on the opening of the file

file = File.open "acao_e_reacao_utf16_le.txt", "rb:utf-16le"
 => #<File:acao_e_reacao_utf16_le.txt> 

file.external_encoding
 => #<Encoding:UTF-16LE> 

file.internal_encoding
 => nil 

str = file.read
 => "A\u00E7\u00E3o e Rea\u00E7\u00E3o" 

str.encoding
 => #<Encoding:UTF-16LE> 

str.encode(Encoding::UTF_8)
 => "Ação e Reação"