hexdump confusion

Question

I am playing with the Unix hexdump utility. My input file is UTF-8 encoded, containing a single character ?, which is C3 B1 in hexadecimal UTF-8.

hexdump test.txt
0000000 b1c3
0000002

Huh? This shows B1 C3 - the inverse of what I expected! Can someone explain?

For getting the expected output I do:

hexdump -C test.txt
00000000  c3 b1                                             |..|
00000002

I was thinking I understood encoding systems.

Answer 1

This is because hexdump defaults to using 16-bit words and you are running on a little-endian architecture. The byte sequence b1 c3 is thus interpreted as the hex word c3b1. The -C option forces hexdump to work with bytes instead of words.