This particular usage of split removes all whitespace, not split in general. If you split on something more specific such as a space or a tab then the newline will still be found in the last element of the list.

use Data::Dumper;

while (<DATA>) {
    my @foo = split;
    my @bar = split / /, $_;
    print Dumper \@foo, \@bar;
}

__DATA__
hello world
foo bar baz
[download]

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)