Re^2: How can one get all possible combinations of elements of different arrays using File::Glob(bsd_glob)?

[jwkrahn]

# slurp in file into a string
$/=''; $DNA = <FILE>; 
# remove \n at end
chomp($DNA);

You have set $/ to paragraph mode so it will not "slurp in file", just the first paragraph of the file.    Also the value of $/ will effect what chomp removes (hint: paragraph mode removes more than just a single \n character).

# replace line endings with commata
$DNA =~ s/\n/,/;

That replaces a single newline.    If you want to replace ALL newlines then:

# replace newlines with commas
$DNA =~ s/\n/,/g;

Or perhaps:

# replace newlines with commas
$DNA =~ tr/\n/,/;