this :

        ...
        my $row;
        @$row = split(/,/, $line );
        push @$sheet2 , $row;
        ...
[download]

OR

    ...
    my @row = ();
    @row = split(/,/, $line );
    push @sheet2 , \@row;
    ...
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Could be written like this in one line instead of three

   ...
   push @sheet2, [ split(/,/, $line ) ];
   ...
[download]

And there is no need for the array variable row at all.
You could use Data::Dumper to view your variable @sheet2 to confirm.