Platform independant what of generating Linux compatible crypt(3) sha512 hashes ($6$ style). For systems (like macOS/OSX) where you can't `mkpasswd -m sha-512`.

mkpasswd.py

#!/usr/bin/env python3

# Because OSX doesn't have mkpasswd...

# Based on https://stackoverflow.com/a/17992126/117471
# python3 -c "from passlib.hash import sha512_crypt; print(sha512_crypt.encrypt(input()))" <<< bruno  # NOQA

# Usage:
#
# $ ./mkpasswd.py
# Password:
# $6$rounds=656000$pfFmQISGcjWHOCxW$rBptiSK.tqSPnUiq6KiSHzz6LvvW/x1SjkkWFwxWB9Dt75NLNBs0N3OyGV4K5ejjBs/u.o3jtigvUKbmmwVQP.
#
# $ PROCESS_TIME=1 ./mkpasswd.py
# Password:
# $6$rounds=656000$e0OGrad82DBrUo9T$ldqtOdN54gmXI6nb0D.Y5mm5ih.LIQm/Ep/bkNL76.3hE65FqXA9wyZ.M5YOrv6dSvwhPAktXGJ6LJT0Fgd4x.
# 656000 rounds in 1.008705 seconds of cpu time
#
# $ ROUNDS=1280000 PROCESS_TIME=1 ./mkpasswd.py <<< bruno
# $6$rounds=1280000$QO5FSyw5rQpiY6PI$0zRMJ4RzCbH61XxIdpsUm/79.VZ13Mm9TBN9GvJwt1LI1U5FVzakrLya5VJsXlTou3p5ZeWmo29bIUjubRuc31
# 1280000 rounds in 1.9206560000000001 seconds of cpu time

import os
import sys
import time
from getpass import getpass
from passlib.hash import sha512_crypt

rounds = os.environ.get('ROUNDS')
if not rounds:
    rounds = sha512_crypt.default_rounds

passwd = input() if not sys.stdin.isatty() else getpass()

proc = sha512_crypt.using(rounds=rounds)
start = time.process_time()
out = proc.encrypt(passwd)
end = time.process_time()

print(out)

if os.environ.get('PROCESS_TIME'):
    print('{} rounds in {} seconds of cpu time'.format(rounds, end-start))