Thanks for clarifying that ' ' is DWIM (magical) with respect to leading whitespace.

#!/usr/bin/perl

use Data::Dumper;

$_ = " foo bar baz ";

my @a = split ' ';
my @b = split /\s+/;

print Dumper \@a;
print Dumper \@b;

__DATA__
$VAR1 = [
          'foo',
          'bar',
          'baz'
        ];
$VAR1 = [
          '',
          'foo',
          'bar',
          'baz'
        ];
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What interests me from a 'why is it so?' point of view is that if \s+ splits at the begining of a string to find the NULL why not at the END as well. Your example documants the behaviour but why is leading whitespace treated differently from trailing whitespace? There is afterall a null string after the trailing whitespace as well.