Linux Common Commands (2)-User and user group management __linux

# ID # Displays the ID of the current user and user group
# who shows user information for the current login system
#su change user identity
[root@localhost/] #su chenlly
[chenlly@localhost/]

#cat/ETC/PASSWD Archives Structure
Root:x:0:0:root:/root:/bin/bash
chenlly:x:1000:1000:chenlly,,,:/home/chenlly:/bin/bash
Sshd:x:114:65534::/var/run/sshd:/usr/sbin/nologin
Oracle:x:1001:1001::/home/oracle:/bin/bash
1001 of which correspond to UID and GID
Uid:id Range
When the UID is 0 o'clock, this account is the system administrator.
1~499 SYSTEM Account
500~65535 (can login account) for general users

#cat/ETC/SHADOW Archives Structure
Chenlly:$6$vct89b4h$4zdiu2.uwvfrcloe6uchp7avkscrgk2bcmq.. Bdgmniujwof0ida1qflpwsptse2snnlnfihd5bl0ifdjtqtk/:15595:0:99999:7:::
Sshd:*:15595:0:99999:7:::
oracle:$6$6l0houuo$lczjf8rah1eiy2fw8v4610vwfv7awpdqblh6x1uqcfwajpxhtoodl1mzgc0pwhpzlrlu4pszjyj0hw.4xkolq/ : 15595:0:99999:7::
Store the account password, and the password is encrypted.

#cat/ETC/GROUP Archives Structure
root:x:0:
chenlly:x:1000:
1. Group name 2. Group Password 3.GID:

#groupadd-G 412400 CDL creates a group CDL and assigns it an ID number 412400
Delete a group #groupdel CDL
#groups chenlly View the group to which the user chenlly belongs
#useradd chenlly-u 3466-g 412400 (or group name) to create a user and add a group ID of 412400 and can follow the group list
#usermod-G LDC Chenliling77 modifies a user (Chenliling77 originally belonged to the CDL Group) to the LDC group
#userdel chenlly Deletes a user
#passwd chenlly Add/Modify Password
#id chenlly View the user ID and the owning group ID

Simply using the Useradd defaults will help us with several projects:
Set up a line of data related to account in/etc/passwd, including setting up Uid/gid/home directory;
In/etc/shadow, the password-related parameters of this account are filled in, but the password is not yet available;
In/etc/group, add a group name that does not have an exact name;
Create a directory under/home with the same name as the user's home directory, and the permission is 700;