our $dest_book = Spreadsheet::WriteExcel->new("Report.xls");
my $diskusage = $dest_book->add_worksheet("01-diskcheck");
my $c3format = $dest_book->add_format();
my $lightgreen = $dest_book->set_custom_color(41,10,255,133);

$c3format->set_valign('vcenter');
$c3format->set_align('center');
$c3format->set_border('1');
$c3format->set_bg_color($lightgreen);

$diskusage->write('F2','=IF(E2<D2,"normal","failed")',$c3format);
$diskusage->write('F3','=IF(E3<D3,"normal","failed")',$c3format);
$diskusage->write('F4','=IF(E4<D4,"normal","failed")',$c3format);
$dest_book->close();