use SharedVariables qw(:DEFAULT);
use Foo;
use Bar;

$scalar1 = 'Initialized';

print "Main Scalar1 $scalar1\n";
Foo::Print;
Foo::Set;
Foo::Print;
Bar::Print;
Bar::Set;
Bar::Print;
$scalar1 = 'Main';
Foo::Print;
Bar::Print;

__END__
C:\temp> test.pl
Main Scalar1 Initialized
Foo Scalar1 Initialized
Set Foo
Foo Scalar1 Foo
Bar Scalar1 Foo
Set Bar
Bar Scalar1 Bar
Foo Scalar1 Main
Bar Scalar1 Main