"..I want to convert the log files to xls. by bash script I converted it to csv.."

Since you have a csv file already, you will need Text::CSV_XS or Text::CSV module to read in your csv file and Spreadsheet::WriteExcel to write into an excel file as mentioned by marto.
Something like so:

#!/usr/bin/perl
use strict;
use warnings;
use utf8;

use Spreadsheet::WriteExcel;
use Text::CSV_XS;

my $csv = Text::CSV_XS->new( { binary => 1, allow_loose_quotes => 1, }
+ )
  or die "can't open CSV file" . Text::CSV_XS->error_diag();

my $wrkbook  = Spreadsheet::WriteExcel->new('new_file.xls');
my $wrksheet = $wrkbook->add_worksheet('new_file');

open my $fh, "<:encoding(utf8)", "Data.csv" or die "can't open file: $
+!";
while ( my $row = $csv->getline($fh) ) {
    $wrksheet->write_row( $., 0, [ @{$row} ] ); ## write to excel file
}
$csv->eof or $csv->error->diag();
close $fh or die "can't close file:$!";
[download]