my $test="my_variable_name";
my $default_value="the value I set";

$default_value = *$test;
$$default_value = "old value";

print "the value of \$my_variable_name = $my_variable_name\n";
$my_variable_name = "A new value";
print "the value of \$my_variable_name = $my_variable_name\n";