I like the autovivification in 5.6.0:

#!/usr/bin/perl

use strict;
use warnings;

{
    my %file_handle;
    while (<DATA>) {
        my ($id, $category, $sub_category, $code, $description, $pictu
+re) =
             split /\|/;
        # massage data into a printable string

        $file_handle{$sub_category} ||= get_handle($sub_category);

        print {$file_handle{$sub_category}} "something\n";
    }
}   # As %file_handle goes out of scope
    #   all file handles close implicitly

sub get_handle {
    my $file_name = shift;
    open my $fh, '>', $file_name or die "Cannot write to $file_name: $
+!";
    return $fh;
}


__END__
0|OFFICE EQUIPPMENT|PEN|PDS01|an ordinary pen|pen.gif
1|OFFICE EQUIPPMENT|PEN|PDS02|another pen|pen2.gif
2|OFFICE EQUIPPMENT|PAPER|PA003|white sheets to write on|paper.gif
3|OFFICE EQUIPPMENT|PEN|PDD50|the greatest pen|pen50.gif
4|OFFICE EQUIPPMENT|PEN|PDS01|an ordinary pen|pen.gif
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HTH,
Charles K. Clarkson