Select Code to Download

   @ARGV or die "No input file specified";
    open my $first, '<',$ARGV[0] or die "Unable to open input file: $!
+";
    open my $second,'<', $ARGV[1] or die "Unable to open input file: $
+!";
...
    else{next;}
    }
    }

   @ARGV or die "No input file specified";
    open $first, '<',$ARGV[0] or die "Unable to open input file: $!";
    open $second,'<', $ARGV[1] or die "Unable to open input file: $!";
...
    }
    }
    }