$(сабж) в следующем куске кода
irb(main):115:0> a = {:t1 => 'sa ma ra', :t2 => 'John'}
=> {:t1=>"sa ma ra", :t2=>"John"}
irb(main):116:0> b = a.clone
=> {:t1=>"sa ma ra", :t2=>"John"}
irb(main):117:0> b
=> {:t1=>"sa ma ra", :t2=>"John"}
irb(main):118:0> b[:t2] = 'Jack'
=> "Jack"
irb(main):119:0> a
=> {:t1=>"sa ma ra", :t2=>"John"}
irb(main):120:0> b
=> {:t1=>"sa ma ra", :t2=>"Jack"}
irb(main):121:0> b[:t1].sub!('ma', 'ha')
=> "sa ha ra"
irb(main):122:0> b
=> {:t1=>"sa ha ra", :t2=>"Jack"}
irb(main):123:0> a
=> {:t1=>"sa ha ra", :t2=>"John"}
irb(main):124:0>
