> perl -lwe '$x=$y=0; foreach $x (0..9) { ++$y } print "$x, $y"'
0, 10
> perl -lwe 'my($x,$y)=(0,0); foreach $x (0..9) { ++$y } print "$x, $y"'
0, 10
> perl -lwe '$y=0; foreach $x (0..9) { ++$y } print ! defined $x,", $y"'
1, 10
> perl -lwe 'my $y=0; foreach my $x (0..9) { ++$y } print ! defined $x,", $y"'
Name "main::x" used only once: possible typo at -e line 1.
1, 10
>