My Linux path----user and group and password management

User's creation and deletion:

1. Useradd adding users

   -U Specify UID

   -D Specify the user's home directory

   -M does not set up a home directory, if you want to create a home directory: You can create a home directory, such as Mkdir/home/username, and then

   cp/etc/skel/.ba*/home/username, you can log in to the home directory.

   -S Custom shell

2. Userdel Deleting a user

   -R Delete the user at the same time, along with the home directory deleted

3. Groupadd Adding user groups

4. Groupdel Deleting a user group
   

   -G Specify GID

5. Usermod Modifying user information

   -D Modify Home directory

   -G Modify User Group

   -S Modify shell

   -G adds a user to the group

   -L Lock User

   -U Unlock User

   Note: Passwd-l is also a lock user

   Passwd-u is also unlocking the user

   
   

   Passwd-l Lock the user, in the/etc/passwd can see the locked user password in front of two!

   Usermod-l Lock the user, in/etc/passwd can see the password is locked before the user is a!.

   Unlock the user with usermod-u, unlock!!, need to be unlocked two times.

   Unlock the user with passwd-u, unlock!!, once and then OK.

6. CHFN Username Modify User's description information

   Example: hua:x:500:500:huhu,11111,1111,1111:/home/hua:/bin/bash

Password Management:

1. /ETC/PASSWD configuration information for users

   ①shan:②x:③501:④501:⑤:⑥/home/shan:⑦/bin/bash

   ① User Name

   ② User Password

   ③uid

   ④gid

   ⑤ description information about the user, CHFN username can be used to add descriptive information

   ⑥ User's home directory

   ⑦ User's shell environment

2. /etc/shadow User Password configuration information

   ①shan:②$6$v4bjzenc$apntkkchk0a/1i7oakx0oykiy2. Nprxx23xlzd09omfyrwq3yx6jnxst9va.4g8.jst.jxmh8zcyvem/bl6w.:③16699:④0:⑤99999:⑥7:⑦:⑧:⑨

   ① User Name

   ② password, this is an encrypted password, $6 represents sha-512,$5 on behalf of the SHA-256,$1 representative MD5.

   ③ the last date the password was modified, expressed as the number of days from January 1, 1970.

   ④ the number of days from which a password can be changed, 0 means no limit and can be changed at any time.

   ⑤ the maximum number of days that a password must be changed

   ⑥ number of days before the account expires in advance warning

   ⑦ the number of days that a user can still be used after a password expires

   ⑧ account expiration date, expressed as the number of days from January 1, 1970.

   ⑨ reserved for future use
   

This article is from the "My Linux Road" blog, so be sure to keep this source http://8641765.blog.51cto.com/8631765/1696672

My Linux path----user and group and password management