Redhat chapter 3 Managing Users and Groups

1. User can be People or account that exsist for certain application
2. User assosiated with User ID and Group with Group ID (reserved userid 0-500)
3. Owner = if user create file he become the owner
4. Owner change only by ROOT
5. In file there is permission read, write, exsecutable for user, group and everyone
6. File permission Only changed by ROOT and the Owner
7. User private group is added when user is created on the system with the same name as user name
8. UMASK = the setting that determines what is permission of newly created file
9. UMASK setting on /etc/bashrc
10. SHADOW PASSWORD = provide more security
11. SHADOW PASSWORD move readable password on /etc/passwd to /etc/shadow

12. command that cannot use if Shadow Pass has't set
Change, Gpasswd, usermod and useradd with -e and -f
13.  user properties >>
user data (user's full name, password, home directory, or login shell),
account info (Enable account expiration, Local password is locked [user cannot login]),
password info (date that the user's password last changed, Enable password expiration,
Days before change required),
groups
14. if you USERDEL user, the group is also deleted