#!/usr/bin/perl  
use strict;
use warnings; 
use File::Glob qw{bsd_glob};
############################################
## Output to a TEXT File using file handle: 
############################################
 my $output="joint.txt";
 open (my $fh,">",$output) or die"Cannot open file
  '$output'.\n";  
############################################
my $string;
my $entry;
do {
  print"\n\n Press 1 to Enter New File or 2 to Combine:  ";
  $entry=<STDIN>; chomp $entry;  
  if ($entry==1) { 
    print"\n\n    Enter New File Name (.txt):  "; 
    my $filename = <STDIN>; 
    chomp $filename;
    open my $fh, "<", $filename or die "Cannot open $filename.\n";
    my $DNA;
    {
      local $/=undef;
      $DNA = <$fh>;
    }
    close $fh;
   
    chomp $DNA;
    $DNA=~s/\n/,/g;
    $DNA=~s/,+$//g;  # To remove multiple comma created by empty lines in txt file
    $DNA=~s/,,+/,/g; # To remove trailing comma created by empty lines in txt file
    $string .= "{$DNA}";
  }      # Curly brace for entry1 ends:  
} until ($entry==2);
for (bsd_glob $string) {
  print"\n"; 
  print "~$_~\n";
  print $fh "~$_~\n";
}

close $output;    
exit;  
#############################################