For constructs that do interpolate, variables beginning
   with ""$"" or ""@"" are interpolated, as are the following
   escape sequences.

##</code><code>##

  use Data::Dumper;
  print Dumper \%hash;

  print join ":", %hash;

  print join ":", keys %hash;
  print join ":", values %hash;

  while( my ($k, $v) = each %hash ){
    printf " %s --> %s\n", %k, $v;
  }