use strict;

my $var= "Hello, World!";
for(  my $copy= $var  ) {
    s/World/Earth/;
    print $_, $/;
}
print $var, $/;
eval 'print $copy, $/; 1'
    or  print '$copy no longer in scope', $/;
__END__
Hello, Earth!
Hello, World!
$copy no longer in scope