How to get a random string of 32 hexadecimal digits through command line?

Question

If you have hexdump then:

hexdump -vn16 -e'4/4 "%08X" 1 "\n"' /dev/urandom

should do the job.

Explanation:

-v to print all data (by default hexdump replaces repetition by *).
-n16 to consume 16 bytes of input (32 hex digits = 16 bytes).
4/4 "%08X" to iterate four times, consume 4 bytes per iteration and print the corresponding 32 bits value as 8 hex digits, with leading zeros, if needed.
1 "\n" to end with a single newline.