#!/usr/bin/perl

use strict;
use Text::CSV;

my $old_string;
my $csv = Text::CSV->new();
while ( my $line = <DATA> ) {
    $old_string = $old_string . join( " ", $csv->fields() ) . "\n"
      if ( $csv->parse( $line ) );
}

my @new_string = map { $_->[0] }
                 sort { $a->[1] cmp $b->[1] }
                 map { [$_, (split)[4]] }
                 split( /\n/, $old_string );

# Recreating the CSV data.
foreach my $i (@new_string) {
    my $j = join "\",\"", split( " ", $i);
    print "\"$j\" \n";
}

__DATA__
"Task1,Task2",ABC,ABC,Mon 05/22/2009,mbm
"Task3,Task4",XYZ,XYZ,Mon 05/20/2009,mbm
"Task5,Task6",ABC,ABC,Mon 06/25/2009,mbm
"Task7,Task8",ABC,ABC,Mon 03/28/2009,mbm