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

my $line = "36,'', NULL, '', 'on', '', 300";
my @tokens = split(/\,\s*/, $line);
foreach (@tokens)
{
   $_ = "''" if $_ eq 'NULL';
   print "$_\n";
}

__END__
36
''
''
'' ## NULL is now an empty string
'on'
''
300

##</code><code>##

foreach (@tokens)
{
   $_ //= '';  #sets undefined value to empty string
               #the // operator (new in Perl 5.10) tests
               #for "defined-ness" instead of truthful-ness.
   print "$_\n";
}

##</code><code>##

__DATA__
3,  0, 0, 3,  2, 'on', 'host_description - Hard Drive Space',      '', NULL, '', 'on', '', 300, ''
4,  0, 0, 4,  1, '',   'host_description - CPU Usage - System',    '', NULL, '', 'on', '', 300, ''
5,  0, 0, 5,  1, '',   'host_description - CPU Usage - User',      '', NULL, '', 'on', '', 300, ''
6,  0, 0, 6,  1, '',   'host_description - CPU Usage - Nice',      '', NULL, '', 'on', '', 300, ''
7,  0, 0, 7,  2, 'on', 'host_description - Noise Level',           '', NULL, '', 'on', '', 300, ''
8,  0, 0, 8,  2, 'on', 'host_description - Signal Level',          '', NULL, '', 'on', '', 300, ''
9,  0, 0, 9,  2, 'on', 'host_description - Wireless Transmits',    '', NULL, '', 'on', '', 300, ''
10, 0, 0, 10, 2, 'on', 'host_description - Wireless Re-Transmits', '', NULL, '', 'on', '', 300, ''

##</code><code>##

3,  0, 0, 3,  2, 'on', 
4,  0, 0, 4,  1, '',   # 4,  0, 0, 4,  1, 'off'
5,  0, 0, 5,  1, '',   # 5,  0, 0, 5,  1, 'off',
6,  0, 0, 6,  1, '',   # 6,  0, 0, 6,  1, 'off', 
7,  0, 0, 7,  2, 'on', 
8,  0, 0, 8,  2, 'on', 
9,  0, 0, 9,  2, 'on', 
10, 0, 0, 10, 2, 'on',