>perl -wMstrict -le
"sub test (\%);
 ;;
 my %Record1 = ( username        => '$' ,
                 password        => '$' ,
                 emailAddress    => '@' );
 my $hashref = \%Record1;
 ;;
 print $Record1{username};
 $hashref->{username} = 'NOOoooooo!';
 print $Record1{username};
 test(%Record1);
 print $Record1{username};
 ;;
 sub test (\%) {
   my $reference = shift;
   my $test = q{Pigsy's Perfect Ten};
   $reference->{username} = $test;
   print 'in test(): ', $reference->{username};
   }
"
$
NOOoooooo!
in test(): Pigsy's Perfect Ten
Pigsy's Perfect Ten