How to calculate hexadecimal xor (^) from shell?

Question

Unfortunately bc and calc don't support xor.

score 41 · Accepted Answer · answered Jun 27 '16 at 10:26

41

Like this:

echo $(( 0xA ^ 0xF ))

Or if you want the answer in hex:

printf '0x%X\n' $(( 0xA ^ 0xF ))

On a side note, calc(1) does support xor as a function:

$ calc
base(16)
    0xa
xor(0x22, 0x33)
    0x11

answered Jun 27 '16 at 10:26

Satō Katsura

1

In case your numbers are binary: `printf '0x%X\n' $(( 2#1010 ^ 2#1111 ))` – Matthias Braun Feb 10 '22 at 16:50

score 23 · Answer 2 · answered Jun 27 '16 at 10:25

23

With any POSIX shell:

$ printf '%#x\n' "$((0x11 ^ 0x22))"
0x33

answered Jun 27 '16 at 10:25

`%#x` works in C too, nice! – Zombo Jun 27 '16 at 22:54
2

@StevenPenny, note that one difference with `0x%x` is that it gives `0` instead of `0x0` for 0. – Stéphane Chazelas Jul 27 '20 at 11:36

score 14 · Answer 3 · edited Jun 28 '16 at 08:49

14

gdb has powerful expression calculator:

gdb -q -ex 'print/x 0xA ^ 0xF' -ex q

A shell function:

calc_gdb() { gdb -q -ex "print/x $*" -ex q;}
calc_gdb 0xA ^ 0xF

$1 = 0x5

edited Jun 28 '16 at 08:49

lcd047

answered Jun 27 '16 at 10:22

Costa

4

Amusing, but it seems like a sledgehammer to crack a nut! – abligh Jun 28 '16 at 08:16
1

Useful for the more general case of evaluating expressions, but not for XOR – Peter Cordes Jun 28 '16 at 08:57

score 7 · Answer 4 · answered Jun 27 '16 at 22:23

7

It is possible to do that in bc:

echo 'xor(10,15)' | bc -l logic.bc

Or in hex:

echo 'obase=16;ibase=16; xor(AA,FF)' | bc -l logic.bc

Just do wget http://phodd.net/gnu-bc/code/logic.bc to get it.

answered Jun 27 '16 at 22:23

Wow, that site is the `bc(1)` geek's heaven. :) Thank you for the link. – Satō Katsura Jun 28 '16 at 17:24
My version of "bc" doesn't seem to have the XOR function and just says: `Runtime error (func=(main), adr=51): Function xor not defined.` – slacy Oct 05 '16 at 21:13
@slacy did you get the `logic.bc` file referenced there? That is what defines `xor` it seems – Eric Renouf Oct 11 '16 at 17:53

4 Answers4