"i had to write a csv sorting code for which i used the following code :"

i wrote this multithreaded program to sort files in parallel ,this was actually the subroutine part (sort of).initial code which i tried would append sorted line to previous line, so 2 lines would be clubbed in 1 line ; hence i found THIS code on net

initial code below

foreach(@csvfiles) {
    $csvfile=$_;
    open(hanr,"D:\\stock\\".$csvfile) or die"error read $!\n";
    open(hanw,">D:\\stock\\sorted".$csvfile) or die"error write $!\n";
    @lines = ();
    @lines = <hanr>;
    shift(@lines);#remove header csv                        
    @sorted = sort multisort @lines;
    sub multisort {
                    ($field1a, $field2a, $field3a)=split(/\,/, $a); 
                    ($field1b, $field2b, $field3b)=split(/\,/, $b);
                    $field1a cmp $field1b or $field2a cmp $field2b; 
                  } 
print hanw @sorted;
close(hanw);
close(hanr);
}
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