Get user to specify sequence file and print out orginal strand sequence and reverse complementary DNA and RNA

wholeShebang.pl

#!/usr/bin/perl

use strict;
use warnings;

print "Which file would you like to use?\n";

my $DNAfilename = <>;

open(DNAfile, $DNAfilename);

my $DNA1 = <DNAfile>;

close DNAfile;

my $rev = reverse($DNA1);

my $DNA2 = $DNA1;
$DNA2 =~ tr /atcgATCG/tagcTAGC/;

my $RNA = $rev;
$RNA =~ tr /tT/uU/;

print "Original strand in 5' to 3' direction:\n", "$DNA1\n\n", 
"Reverse DNA complement:\n", "$rev\n\n", 
"Reverse RNA complement:\n", "$RNA\n";