Hi Dave, Here is my code:

#!/usr/local/bin/perl
#  Declarations
#===========================================================
use File::Basename;
use Spreadsheet::ParseExcel;
use Text::Iconv;
use Spreadsheet::XLSX;
use IO::Handle;
use encoding 'UTF8';

#  Program proper
# Check the input file provided is a xls or xlsx
#===========================================================

my $input_file_name = shift || usage();

($file,$dir,$ext) = fileparse($input_file_name, qr/\.[^.]*/);

$output_file_name = "$dir/"."$file".".csv";

open FILE, ">$output_file_name";
select FILE;

#===========================================================

parse_excel($input_file_name);

exit 0;

#  Subroutines
#===========================================================

sub parse_excel {

if ($ext eq ".xls") {

    my %arg = ( record_sep => "\n",
#                field_sep  => "\t",
                field_sep  => ",",
                xls        => undef );

    if ( @_ == 1 ) {
        $arg{xls} = shift;
    } elsif ( not @_ % 2 ) {
        %arg = ( %arg, @_ );
    }

    -e $arg{xls} or 
        die "Must provide valid XLS file! $arg{xls}, $!\n";

    # create a ParseExcel object
    my $excel_obj = Spreadsheet::ParseExcel->new();

    my $workbook = $excel_obj->Parse($arg{xls});

    # make sure we're in business
    die "Workbook did not return worksheets!\n"
        unless ref $workbook->{Worksheet} eq 'ARRAY';

    # we need to get each worksheet from the workbook in turn

#    for my $worksheet ( @{$workbook->{Worksheet}} ) 
    my $worksheet = $workbook->Worksheet(0);
 {

    # {Cells}[row][col]
    # empty worksheets have undef for MaxCol and MaxRow
        my $last_col = $worksheet->{MaxCol} || 0;
        my $last_row = $worksheet->{MaxRow} || 0;

        for my $row ( 0 .. $last_row ) {

            for my $col ( 0 .. $last_col) {

                my $cell = $worksheet->{Cells}[$row][$col];

               # print ref $cell ?
               #     $cell->Value : '' ;
        $str = ref $cell ? $cell->Value : '';
                    
        $str =~ s/\s+$//g;

        $str =~ s/\"//g;
                    
        $str =~ s/\r\n//g;

        $str =~ s/amp\;//g;

        $str =~ s/ \d\d\:\d\d\:\d\d//g;

        if ($str =~ /(\d*\d)-(\d*\d)-(\d\d)/) {
         ($m, $d, $y)  = split (/-/, $str);
         #if ($y eq '00') {$y = 0};
         if ($y > 50) {
          $y += 1900;
         } elsif ($y < 50) {
           $y += 2000;
         }
         $str = sprintf '%d/%d/%d', $m, $d, $y;
        }
                        
        if ($row == 0) {
            print $str;
        } else {
            print "\"$str\"";
        }

                print $arg{field_sep} unless $col == $last_col;
            }
            print $arg{record_sep} ; # record ends
        }
        print "\n" ; # worksheet ends
    }
} elsif ($ext eq ".xlsx") {

 my $converter = Text::Iconv -> new ("utf-8", "windows-1252");

    my %arg = ( record_sep => "\n",
#                field_sep  => "\t",
                field_sep  => ",",
                xls        => undef );

    if ( @_ == 1 ) {
        $arg{xls} = shift;
    } elsif ( not @_ % 2 ) {
        %arg = ( %arg, @_ );
    }

    -e $arg{xls} or 
        die "Must provide valid XLS file! $arg{xls}, $!\n";

 my $excel = Spreadsheet::XLSX -> new ($input_file_name, $converter);
# my $excel = Spreadsheet::XLSX -> new ($input_file_name, "");
 
# foreach my $sheet (@{$excel -> {Worksheet}}) 
  my $sheet = $excel -> Worksheet(0); 
{

#        printf("Sheet: %s\n", $sheet->{Name});
        
        $sheet -> {MaxRow} ||= $sheet -> {MinRow};
        
         foreach my $row ($sheet -> {MinRow} .. $sheet -> {MaxRow}) {
         
                $sheet -> {MaxCol} ||= $sheet -> {MinCol};
                
                foreach my $col ($sheet -> {MinCol} ..  $sheet -> {Max
+Col}) {
                
            my $cell = $sheet->{Cells}[$row][$col];
                    
            #print ref $cell ?
            #        $cell->Value : '';
                                
            $str = ref $cell ? $cell->Value : '';
                        
            $str =~ s/\s+$//g;

            $str =~ s/\"//g;
                        
            $str =~ s/\r\n//g;

            $str =~ s/amp\;//g;

            $str =~ s/ \d\d\:\d\d\:\d\d//g;

            if ($str =~ /(\d*\d)-(\d*\d)-(\d\d)/) {
             ($m, $d, $y)  = split (/-/, $str);
             #if ($y eq '00') {$y = 0};
             if ($y > 50) {
              $y += 1900;
             } elsif ($y < 50) {
               $y += 2000;
             }
             $str = sprintf '%d/%d/%d', $m, $d, $y;
            }
                        
            if ($row == 0) {
                print $str;
            } else {
                print "\"$str\"";
            }

            print $arg{field_sep} unless $col == $sheet -> {MaxCol};
 
                }
             print $arg{record_sep}; # record ends
        }
        print "\n"; # worksheet ends
 }
} elsif ($ext ne ".bubba") {
 print "This extension is not supported at this time";
 print "\n";
}
}
CLOSE FILE;
#===========================================================
sub usage {

    my ( $tool ) = $0 =~ m,([^\/]+$),;

    print <<HERE;
------------------------------------------------------------
USAGE:

   $tool EXCEL_FILE.xls || EXCEL_FILE.xlsx

Takes an Excel file either with a xls or xlsx extension,
parses it into comma delimited fields and rows, and sends
the results to a filename with .csv extension. 
------------------------------------------------------------
HERE
    exit 0;
}
[download]

One could ask "Is there some part of '20-30 lines' you don't understand?"

Immediate apologies included: preceding is for emphasis (despite its regretable hint of rudeness). But perhaps that will also emphasize that boiling down your code to a snippet of 20-30 lines in length (which snippet still displays your problem) will not only make it easier for us to help you (and since you're asking for free help, that's a very good idea) but may also help you directly because confining the error to such a short snippet may make the cause obvious to you!.




On asking for help and How do I post a question effectively?

My sincere apologies and I understand your point. The conversion from xls to csv is working fine meaning input data matches output data. The issue is with second part of this code which is converting XLSX data to csv (line 114 to 190). Here in the output data the TRUE/FALSE strings are getting converted to 1/0 and this is the part I need some help - how to skip or avoid this conversion of TRUE/FALSE strings - leave them as is in the output - same as input. Appreciate your help and time.