https://help.ubuntu.com/community/StrongPasswords and https://askubuntu.com/questions/244115/how-do-i-enforce-a-password-complexity-policy
– RinzwindAug 13 '18 at 06:36
@Rinzwind; thanks but What I want is not 'how to generate passwords' but how to prevent users to manually set weak passwords;
– user3541631Aug 13 '18 at 06:54