perl -wle 'system("ps uch $$");@x=1..1_000_000;print "Elements in \@x: " . @x;; system("ps uch $$");'
xxx      2395  0.0  1.0  46488 44384 pts/0    R+   18:46   0:00 perl
Elements in @x: 1000000
xxx      2395  0.0  1.5  66104 64012 pts/0    R+   18:46   0:00 perl