Here is the video version, if you prefer it:
Have you ever wondered where information about regular users and superusers is kept? The answer is
/etc/passwd maps users to their IDs. It also stores the home directory of the user. Encrypted user passwords are stored in
/etc/shadow. (Ward, 2014) What does “encrypted” mean? It means that passwords are not stored as plain text – they are stored as some jibberish, but there are certain mechanisms which can figure out if a password you enter is valid by manipulating the aforementioned jibberish.
/etc/sudoers is the file containing users that can use the
If you need any details on these files, I think that a Google search can do wonders. I just wanted to cover these files conceptually, so that you heard of them and know what they store.
Hope you learned something new!
Ward, B. (2014). How Linux Works: What Every Superuser Should Know (2nd ed.). No Starch Press. Pages 43; 153-157