Question

I want to print out both the 7th (or whatever) byte and the last byte of a particular file. I want to do this via the command line using the ruby command. (I’m on Mac OS X, but it shouldn’t matter.)

How do I do this?

Answer 1

This prints the integer value of each byte, which is a bit more understandable than your request to print in base 64:

arr = []

f = File.new("/tmp/test.txt")
 # "This is a test sentence.\n"

f.seek(7)
 # => 0 

arr << f.readbyte
 # => [32]    (The space between 'is' and 'a'.)

f.seek(-1, IO::SEEK_END)
 # => 0 

arr << f.readbyte
 # => [32, 10]    (The newline at the end of the file.)