In Unixes that uses the shadow system you just mount the partition and simply delete the string between the first and second colon to clean the password (in the

In Unixes that uses the shadow system you just mount the partition and simply delete the string between the first and second colon to clean the password (in the /etc/shadow file), the string before the first colon is the username, but this only works for the users that do not use another authentication system (such as NIS or Kerberos). Mac OS X (>= 10.5) uses a different system (10.4 uses the netinfo database), the user information (And I guess that the password, as well) are in /var/db/dslocal/nodes/default/users/ in separate .plist files, I could not check if the password hash are included there since my Mac is at home, if I remember about this later I'll try to come with a password cleaning to OS X in this article later. In lilo there is a way to not let the user log in in the single user mode without providing the password, I think that grub could be configured to do the same. So I believe the method that the article describes will not work for every linux installation. By the way, what about some others operating systems, *BSDs, and some that are more exotic (if they use shadow, the method described above works), such as OpenVMS? I do not use windows since forever, so I cannot say much about how the system handles passwords.