$ perl -le'
my @c = 1 .. 10_000_000;
print @c . "  @c[0..19]";
my @e = ( 0 ) x ( @c / 2 );
print @e . "  @e[0..19]";
'
10000000  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
5000000  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0