while (defined (my $line = <STDIN> )) {
        chomp $line;
        my @currentline = split /\s+/, $line;
        $histogram{$_}++ for @currentline;
}

##</code><code>##

if( exists $histogram{$word} ) {
    print "Found $word,  $histogram{$word} times\n";
}

##</code><code>##

use Data::Dumper;

__END__  #Result:
while ( <STDIN> ) {
    my @foo = /(\s+)/;

    print Dumper \@foo;
}

C:\> test.pl
cat food
$VAR1 = [
          ' '
        ];