Linux Note _day06

1. User: identifier, voucher

2. User group: Designator

The process is also owned by the owner and the group

Security context (Secure):

Users: UID,/ETC/PAWWD

Group: GID,/etc/group

Shadow Password:

Users:/etc/shadow

Group:/etc/gshadow

User Category:

Administrator: Uid=0

Normal Users: 1-65535

System User 1-499 (owner of background process)

General Users 500-60000

User Group Category:

Basic group: Default group for users

Private group: When you create a user, a group that has the same name as the user is created by default if the user is not assigned to the group to which they belong.

Additional groups:

Before the process is initiated is an executable file, the permissions of the file prior to execution, the permissions of the process is the identity of the process initiator (processes can use those resource files, determined by the initiator, not the owner of the file)

[[email protected] Eric usr]# Whatis passwdpasswd (1)-Update user ' s authentication tokenspasswd  (5)-Password filepasswd [sslpasswd] (1SSL)-compute password hashes[[email protected] Eric usr]# man  5 passwdthe Field Descriptions Are:account The name of the user on the system.              It should not contain capital letters.  Password The encrypted user password, an asterisk (*), or the letter ' x '.              (See Pwconv (8) for the expla-nation of ' X '.)              UID the numerical user ID.              GID the numerical primary group ID for this user.  GECOS This field was optional and only used for informational purposes.  Usually, it contains the full username.  GECOS means General Electric comprehensive Operating System, which have been renamed to GCOS when  GE ' s large Systems division was sold to Honeywell. Dennis Ritchie hasReported: "Sometimes we sent printer output or batch jobs to the GCOS machine.  The GCOS field in the password file is a place to stash the information for the $IDENTcard.              Not elegant. "              Directory The user ' s $HOME directory.  Shell the program to run at login (if empty, use/bin/sh). If set to a non-existing executable, the user is unable to login through login (1). Default shell

Linux Note _day06