sort file1.csv > file1.sort.csv
sort file2.csv > file2.sort.csv
comm file1.sort.csv file2.sort.csv

##</code><code>##

open FIRST, "first.csv";
while (my $line = <FIRST>) {
    open SECOND, "second.csv";
    while (my $otherline = <SECOND>) {
        if ( $line eq $otherline ) {
            print "Found a match!\n":
        }
    }
    close SECOND;
}
close FIRST;