{
    my $foo = 'X' x 100000000;
    getc;
}
undef $foo;
my $foo = "";
getc;

##</code><code>##

user   12310  2.1  4.8 211000 197024 pts/2
                   
At the second prompt:
user   12310  1.2  4.8 211000 197028 pts/2

##</code><code>##

$foo = 'X' x 100000000;
getc;
undef $foo;
getc;
$foo2 = 'X' x 100000000;
getc;

##</code><code>##

user   15185 18.0  4.8 211000 197020 pts/5
user   15185  5.0  2.4 113340 99364 pts/5
user   15185  4.3  7.2 308660 294684 pts/5