Here is a short example that matches an identifier and highlights it within the line written to an Excel file.

It used Spreadsheet::WriteExcelXML because this type of in-string highlighting isn't (currently) possible with Spreadsheet::WriteExcel. This means, however, that the end user must have Excel 2002/2003.

    #!/usr/bin/perl -w

    use strict;
    use Spreadsheet::WriteExcelXML;

    my $workbook  = Spreadsheet::WriteExcelXML->new("file.xls");
    my $worksheet = $workbook->add_worksheet();

    my $ident = 'days';
    my $row   = 0;

    while (<DATA>) {
        if (s[\b($ident)\b][<B>$1</B>]og) {
            chomp;
            $worksheet->write_html_string($row++, 0, $_);
        }    
    }

    __DATA__
    These are the days and these are the days.
    What are days for?
    This is the time.
    And this is the record of the time.
    I thank you for the days.
[download]

--
John.