perl -wlce 'system("ps uch $$");push @x, $i while ($i++ < 1_000_000);print "Elements in \@x: " . @x;; system("ps uch $$");CHECK { system("ps uch $$") }'
xxx      2521  0.0  0.0   3152  1260 pts/0    R+   18:49   0:00 perl
-e syntax OK