open(FILE1,"<", "file1.txt");
open(FILE2,"<", "file2.txt");
open(FILE3,">", "file3.txt");
my @var1=<FILE1>;
my @var2=<FILE2>;
foreach my $comp1 (@var1) {
foreach my $comp2 (@var2) {
if ($comp1 =~/$comp2/){
print FILE3 $comp1;
}
}
}