sub index_split_join {
    return $_[0] unless index $_[0], 'STOCK' >= 0;  # do a fast check to see if line needs to be looked at
    my @tokens = split /\|/, $_[0];   # split into columns
    $tokens[15] =~ s/STOCK/BOXXE/;    # do replacement in col 16
    return join('|',@tokens);         # glue back together for final result
}