Linux User Management

User account Management:

User account management, add, delete, modify

User Password Management

User Group Management

First, user account management

1. Add User, Useradd

#useradd option User Name

-C Comment Specifies a descriptive description of the annotation

-D directory, specify the home directory, if this directory does not exist, and use the-M option, you can create a master directory at the same time

-G user group, specifying user groups to which users belong

-G user group, specifying additional groups to which the user belongs

-s shell file, specifying the user's login shell

-u user number, specify the user number, and if you have the-o option, you can re-use the other user's identification number

Example:

#useradd-D/home/jason-m Jason

Add a user jason,-d and-m option for user Jason to generate the home directory/home/jason

#useradd-S/bin/sh-g group-g jason,root Jason01

Create a Jason01 user, the login shell is/bin/sh, belongs to group user groups, but also belongs to the Jason and root user group, where group is the primary group

When creating, deleting users,/etc/passwd and/etc/shadow two files will have corresponding user record changes

2. Delete Account

#userdel option User Name

-R to delete the home directory created by the user

Example:

#userdel-R Jason removes Jason users (records in/etc/passwd and shadow files) while deleting user home directories

3. Modify your Account

#usermod option User Name

-C,-D,-M,-G,-G,-S,-u, and-O, these options are the same as in Useradd. Other than that:

-L modified to new user name

Example:

#usermod-L JASON01 Jason changes Jason login username to Jason01

#usermod-S/bin/ksh-d/home/jason01-g developer Jason01

The Jason01 user login shell changed to Ksh, user home directory changed to/home/jason01, user group changed to developer

Second, user password management

The root user can modify the login password of all users, and the normal user specifies to modify their login password.

#passwd option User Name

-l lock password, that is, disable the account

-U password unlock

-D make Account no password

-F forcing users to change their passwords the next time they log on

Example:

If the current user is Jason, the current user password is modified by default

#passwd

Old Password:

New Passwort:

Re-enter new password:

If the root user, the default is to modify the root user password, but can modify the specified user password:

#passwd Jason01 Root user to modify the specified user password, do not need to know the original password

New Passwort:

Re-enter new password:

#passwd-D jason01 Delete the Jason01 user password and do not need to enter the password the next time you log in

#passwd-L JASON01 lock Jason01 user so that they cannot log on

User group management: slightly

Linux User Management