Good example for generating password using different wrappers or bindings of the crypt() function
I use this to manually change password in /etc/shadow for users created only as opensmtpd users which has no shell access (/usr/sbin/nologin)

The quickest way, using python3 is:
python -c 'import crypt; print(crypt.crypt("password",crypt.METHOD_SHA512))'