That won't work when one of the elements is 0, "", "0", undef, etc. Check the size of @one, not whether $entry is true or false.

while (@one) {
   push(@two, pop(@one));
}
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Of course, using reverse would be even better.

.oO( Why doesn't pop return an empty list for an empty array, allowing while (my ($item) = pop(@array))? )

Update: For fun, a few ways to reverse a list:

my @b = reverse(@a);

my @b = sub { my @rv; push(@rv, pop()) while @_; return @rv }->(@a);

my @b = sub { my @rv; unshift(@rv, shift()) while @_; return @rv }->(@
+a);

my @b = map { $a[-$_] } reverse 0..$#a;

my @b = map { $a[-$_] } -$#a..0;

my @b = map { $a[$_] } sort { $b <=> @a } 0..$#a;

my @b = map { $a[$_] } sub { my @rv; push(@rv, pop()) while @_; return
+ @rv }->(0..$#a);

my @b = map { $a[$_] } sub { my @rv; unshift(@rv, shift()) while @_; r
+eturn @rv }->(0..$#a);

my @b = @a[ reverse 0..$#a ];

my @b = @a[ map { -$_ } -$#a..0 ];

my @b = @a[ sort { $b <=> @a } 0..$#a ];

my @b = @a[ sub { my @rv; push(@rv, pop()) while @_; return @rv }->(0.
+.$#a) ];

my @b = @a[ sub { my @rv; unshift(@rv, shift()) while @_; return @rv }
+->(0..$#a) ];
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I keep thinking of more, such as a counting loop...