Does hexdump respect the endianness of its system?

Question

On my machine I get the following output when I run these commands:

$ echo foos > myfile
$ hexdump myfile
6f66 736f 000a

The output from hexdump is little-endian. Does this mean that my machine is little-endian, or does hexdump always use little-endian format?

score 66 · Accepted Answer · edited Aug 26 '19 at 22:52

66

The traditional BSD hexdump utility uses the platform's endianness, so the output you see means your machine is little-endian.

Use hexdump -C (or od -t x1) to get consistent byte-by-byte output irrespective of the platform's endianness.

edited Aug 26 '19 at 22:52

Cory Klein

18,391
26
81
93

answered Nov 14 '12 at 23:55

Gilles 'SO- stop being evil'

807,993
194
1,674
2,175

See also [this answer](https://stackoverflow.com/questions/15553493/how-to-print-only-the-hex-values-from-hexdump-without-the-line-numbers-or-the-as#15554717) for custom formats of `hexdump`'s output. – Matthias Braun Oct 09 '21 at 07:37

score 6 · Answer 2 · edited Jan 30 '19 at 22:46

6

From the manpage:

 -x      Two-byte hexadecimal display.  Display the input offset in hexa‐
         decimal, followed by eight, space separated, four column, zero-
         filled, two-byte quantities of input data, in hexadecimal, per
         line.

...

 If no format strings are specified, the default display is equivalent to
 specifying the -x option.

Your output is little-endian (least significant byte first), which is also the endianness of the x86 and x86_64 architectures, which you are probably using.

edited Jan 30 '19 at 22:46

Cory Klein

18,391
26
81
93

answered Nov 14 '12 at 23:54

Dennis Kaarsemaker

8,420
3
29
31

6

Is it just me, or does the man page not mention anywhere that it is treating the "two-byte quantities" as integers? I thought I was taking crazy pills... – slashingweapon Jun 14 '17 at 21:41
@slashingweapon "two-byte quantity of input data" _is_ `uint16_t` integer. – Ruslan May 08 '18 at 07:53
3

"Two bytes" is not the same as uint16_t on a little-endian system. – slashingweapon May 10 '18 at 16:43
Furthermore, we should stop using this ambiguous term called "byte". If you meant 8-bit units, then "octet" would be precise. – ZeZNiQ Jan 02 '22 at 19:35

Does hexdump respect the endianness of its system?

2 Answers2