open my $file,"<","/path/to/file.txt" or die "Can't read file: $!";
while (<$file>) {  # reads one line of text
   # the line string is in $_
   # the line number is in $.
   if ($. <= 10000) {
      print "ORA found on line $.\n" if /ORA/;
   }
   elsif ($. <= 20000) {
      print "Failed found on line $.\n" if /Failed/;
   }
   else {
      print "File found on line $.\n" if /File/;
   }
}
close $file;