Linux Learning Note 2 users

User

Definition: The user is the identity of the system consumer
The user is stored in the system as a number of channeling characters + several system configuration files
User information involves the system configuration file:
/ETC/PASSWD User Information

User: Password: uid:gid: Description: Home directory: User-used Shell
/etc/shadow User authentication Information
User: Password: Last password modified this time: Minimum validity: Maximum validity: Warning Period: Inactive period: Account expiration date
/etc/group Group Information
Group name: Group password: Group ID: Additional Group member
/etc/gshadow Group Certification Information
/home/username User Home Directory
/etc/skel/.* User Skeleton File

User Action Commands

ID Current View user information
Id-u User UID
-G user GID
-A user all information
-G The ID of the user where all
-un User Name
-GN User Initial Group name
-GN the name of all groups where the user resides
Su-username switching the environment used by user users
echo $PATH View the user environment for the current user
echo $USER display information for the current user

User management (Super User)

Useradd username New User
-U specify UID for user
-G Specify user initial group, this group must exist
-g Specifies the additional group, the same group must exist
-C User Description
-D Specify user home directory
-s Specifies the type of Shell,shell used by the user see/etc/shells

Userdel-r Deleting a user
Groupadd-g New Group,-G indicates the ID of the specified group
Groupdel Deleting a group
passwd Username change user Password

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To view the commands used by the user establishment or management process
Watch-n 1 ' tail-3/etc/passwd;echo==;tail-3/etc/group '

Usermod-u changing user uid
-G change User Initial Group
-G change user Attach Group
-ag Adding user-attached groups
-d change user plus directory information
-MD change user home directory information and home directory name
-S change the user's shell
-C change User's description
-L Freeze User
-U Unlock User

User Empowerment (sudo)

Configuration file for permission devolution action
/etc/sudoers
This file is edited with the Visudo command.
Document content:
Authorized target User Host name = (new user authorized by user) authorize user to execute command

Note: The default is to edit at line 100th, if add nopasswd: You can not enter the password

Example: Enabling student users to create users

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Changes to user password age

Chage-d 0 Secret usage How long, how to set to 0 means the user must change the password before logging on to the system
-M minimum validity period
-M maximum validity
-W Warning Period
-I non-active period
-e Expiration Time format YYYY-MM-DD

Linux Learning Note 2 users