Question

I need to create a script that converts a 4 byte input into its reversed form. I imagine the basic algorithm is something like

1. Read input from STDIN
2. Convert to byte array
3. Reverse the array
4. Write bytes on STDOUT

Any help greatly appreciated.

Answer 1

STDIN.read(4).unpack('C*').reverse.pack('C*')

It reads four bytes from STDIN, unpacks the string as a list of 8 bit unsigned integers, reverses the list and then packs it back as 8 bit unsigned integers.