Q:

In Ruby, Whether I should treat a big file (made up of 4 characters) as Text or Binary?

I'm now going to manipulate large files in Ruby.
What I'm going to do is to add a header line to a gigabyte size file containing a sequence of characters with no new-lines and output the result to a new file. (shown below in example). There can be one of four characters at each position in the sequence (a, c, g, t)
My questions are

Should I open gigabyte size file & ouput file whether as Binary or as Text file?
I'd like to know a sample code. (If possible, I don't want to load all the data of giga-byte size file at once on memory of my computer.)

Thanks.

Example
Suppose the program name is add-header-giga (The 1st argument is header-line and the 2nd argument specifies the input file name. Output file name is output-file)

>cat giga-byte-size-file.txt
cctgcaggagcagagcaaagaggtggccatccgcatctttcgggctgccagtttcgctcctggaggctgtgcag....

>add-header-giga DNA-sequence-from-Homo-Sapiens  giga-byte-size-file.txt

>cat output-file
DNA-sequence-from-Homo-Sapiens
cctgcaggagcagagcaaagaggtggccatccgcatctttcgggctgccagtttcgctcctggaggctgtgcag....

A:

If there's no newlines then it doesn't matter. Binary vs text only differs in their treatment of newlines.

