Convert binary data to hexadecimal in a shell script

Question

I want to convert binary data to hexadecimal, just that, no fancy formatting and all. hexdump seems too clever, and it \"overformats\" for me. I want to take x

Answer 1

Watch out!

hexdump and xxd give the results in a different endianness!

$ echo -n $'\x12\x34' | xxd -p
1234
$ echo -n $'\x12\x34' | hexdump -e '"%x"'
3412

Simply explained. Big-endian vs. little-endian :D

Answer 2

These three commands will print the same (0102030405060708090a0b0c):

n=12
echo "$a" | xxd -l "$n" -p
echo "$a" | od  -N "$n" -An -tx1 | tr -d " \n" ; echo
echo "$a" | hexdump -n "$n" -e '/1 "%02x"'; echo

Given that n=12 and $a is the byte values from 1 to 26:

a="$(printf '%b' "$(printf '\\0%o' {1..26})")"

That could be used to get $n random byte values in each program:

xxd -l "$n" -p                   /dev/urandom
od  -vN "$n" -An -tx1            /dev/urandom | tr -d " \n" ; echo
hexdump -vn "$n" -e '/1 "%02x"'  /dev/urandom ; echo