my $aleph = test(1,2);
my $test = $_;
print "$aleph : $test";
sub test {
    my ($a, $b) = @_;
    $_ = 'test';
}

##</code><code>##

my $aleph = test(1,2);
my $test = $_ ? $_ : '$_ is empty';
print "$aleph : $test";
sub test {
    local $_;
    my ($a, $b) = (@_);
    $_ = 'test';
}