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

use OpenOffice::OODoc;

   ## module version 2.125.3, from Debian Perl Group, installed with:
   ## apt install libopenoffice-oodoc-perl 

open (my $out, '>', "outfile.txt") or die $!;

my $file = ooFile("myspreadsheet.ods");

my $content = odfText(file => $file, part => 'content') or die $!; 
 # Note: "odfText can be used in place of ooDocument()
 # if the calling application is only text-focused 
 # We aren't interested in formats or styles. Perldoc"

## Write to a file the content of the non empty cells 
## in the interval B1:G2001 from "sheet2" to "sheet9" 
## in the .ods libreoffice spreadsheet.

foreach my $sheet (1...8){
 foreach my $row (0...2000){
     foreach my $col (1...6){
       my $value = $content->getCellValue($sheet,$row,$col);
       next if $value eq "";                # next if cell is empty
       next if $value eq "Don't keep this"; # or if match some pattern
       print $out $value,"\n"}  # print cell content to outfile
     print $out "\n";}          # and a newline at the end of each row
 print "okay, next sheet\n-------\n";
}; 

close $out;