Add common new users in Linux

Article Title: add common new users in Linux. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
A super user (also known as "root") is a special account with the power to modify any file in the system. In daily work, it is best not to use a super user account to enter the system, because any wrong operation may cause huge losses. A super user account is the only account provided after the system is created. Therefore, you need to create and use a general user account for daily work.
　　
A super user can create a new user account. the following command creates a new user named zzp:
　　
# Adduser zzp
　　
# Passwd zzp (enter the password of zzp)
　　
Linux uses a policy that separates system administrators from general users. this policy ensures system robustness, at the same time, it also makes it difficult to write viruses in Linux (the program you write only has the write permission on your own directory, and is isolated from other parts of the operating system ).
　　
Generally, you need to modify your password immediately when registering for the first time. The command is as follows:
　　
(Current) Unix Password [enter the old Password]
　　
New Unix Password [enter a New Password]
　　
Retype New Unix Password
　　
[Enter a new password again]
　　
For security reasons, the password you typed is not displayed on the screen.
　　
Weak passwords are the primary cause of system insecurity. For example, use the word "password" as the password; use the name or registration name of yourself or another person as the password; use the company name, department name, or group name as the password; and use the birthday as the password; write the password on the calendar or beside the computer; use words or frequently used words in a dictionary. A good password should contain at least six letters, including letters and numbers, and should be modified frequently.
　　
The system administrator can configure a program to set a password security policy. For example, you can start the linuxconf utility as root for account configuration and change. If you forget the superuser password, you can only use the Linux boot disk to start the system, find the Linux partition on the hard disk, and then edit the/etc/passwd file. in this file, delete the encrypted password of the root user.
　　
Assume that the root registration items in/etc/passwd are as follows:
　　
Root: x: 0: 0: root:/bin/bash
　　
"X" indicates the encrypted password. you should change it to the following format:
　　
Root: 0: 0: root:/bin/bash
　　
Currently, root does not have a password, so you can restart the machine. at the registration prompt, register with root and press the key when prompted to enter the password.
　　
Another solution is to reinstall the system.
　　
If a common user (non-root) forgets his/her password, it is easy to solve. root can modify the password of any user.