Character escaping in Ruby

gistfile1.txt

irb(main):051:0> puts 'foo\bar'
foo\bar
nil
irb(main):052:0> puts 'foo\\bar'
foo\bar
nil
irb(main):053:0> puts 'foo\\\bar'
foo\\bar
nil
irb(main):054:0> puts 'foo\\\\bar'
foo\\bar
nil
irb(main):055:0> puts "foo\bar"
foar
nil
irb(main):056:0> puts "foo\\bar"
foo\bar
nil
irb(main):057:0> puts "foo\\\bar"
fooar
nil
irb(main):058:0> puts "foo\\\\bar"
foo\\bar
nil
irb(main):059:0> WAT
NameError: uninitialized constant WAT
  from (irb):59
	from /Users/rafbm/.rbenv/versions/2.0.0-p0/bin/irb:12:in `<main>'
irb(main):060:0>