open ( my $d , ">>", "dest" ) or die "Could not open destination file : $!\n";
open ( my $s, "<", "source" ) or die "Could not open source file: $!\n";
    while(<$s>){
      chomp;
     print {$d} $_,$/;
    }
 close $s or die "can't close file:$!";
 close $d or die "can't close file:$!";