#!/usr/bin/perl -w
use strict;

my $line = "tok1 \t \t\t tok4\n";

chomp ($line);         #try running without this!
my @x = my ($tok1, $tok2, $tok3, $tok4) = split(/\t/,$line);
foreach my $token (@x)
{
   print "token = $token..\n"; #.. is there to show blanks
}
__END__
prints:
token = tok1 ..
token =  ..
token = ..
token =  tok4..