use strict;
use warnings;

while( my $str = <DATA> )
{
    chomp $str;

    print "\nsplitting $str with these LIMITs:\n";

    foreach my $limit ( 0, 5, 7, -1 )
    {
        my $result = munge( $str, $limit );
        printf "   %2d => [$result]\n", $limit;
    }
}

sub munge
{
    my ( $str, $limit ) = @_;

    my @fields  = split( '\|', $str, $limit );
    @fields  = map { $_ || 'empty' } @fields;

    # using a different delimiter to illustrate non-split fields
    return join( '!', @fields );
}

__DATA__
1|2|3|4|5|6
1|2||4||
|2|3|||
|||||