my $sstr = "my string";
my $rsstr = \$sstr;


print "org str '$sstr'; addr: '" . \$sstr . "'\n";

$sstr .= " + my string add";

print "rs 1 str '$sstr'; addr: '" . \$sstr . "'\n";

$$rsstr .= " + add to ref";

print "rs 2 str '$sstr'; ref: '" . $rsstr . "'; addr: '" . \$sstr . "'\n";