New Tricks: view all users in Linux

Article Title: novice: view all users in the Linux operating system. Linux is a technology channel of the IT lab in China. Including desktop applications, Linux system management, kernel research, embedded systems, open source, and other basic categories 1. view all users in Linux
　
In linux, there are no convenient commands like windows's net user and net localgroup to manage users.
　
The Xwindows interface is not mentioned.
　
(1) in the terminal. You only need to view the/etc/passwd file.
　
(2) Check the third parameter: more than 500, which is the user created later. Others are system users.
　
Or use cat/etc/passwd | cut-f 1-d:
　
2. User management commands
　
Useradd Note: Add a user
　
Adduser Note: Add a user
　
Passwd Note: set a password for the user
　
Usermod Note: to modify user commands, you can use usermod to modify the logon name and user's home directory;
　
Pwcov Note: Synchronize users from/etc/passwd to/etc/shadow
　
Pwck Note: pwck verifies whether the content of the user configuration file/etc/passwd and/etc/shadow is legal or complete;
　
Pwunconv Note: it is the vertical reverse operation of pwcov. It is to create/etc/passwd from/etc/shadow and/etc/passwd, and then delete the/etc/shadow file;
　
Finger Note: Tools for viewing user information
　
Id Note: view the UID, GID, and user group of the user.
　
Chfn Note: Change User information tool
　
Su Note: User Switching Tool
　
Sudo Note: sudo uses another user to execute commands (execute a command as another user), su is used to switch users, and then the user to complete the corresponding tasks through the switch, however, sudo can directly execute the following commands. For example, sudo can execute root authorization without the root password. Only root can execute the corresponding commands; however, you must edit/etc/sudoers through mongodo;
　
Except do note: visodo is the command for editing/etc/sudoers. You can also use vi to edit/etc/sudoers;
　
Sudoedit Note: similar to the sudo function;
　
3. Tools or commands used to manage user groups;
　
Groupadd Note: Add a user group;
　
Groupdel Note: delete a user group;
　
Groupmod Note: Modify user group information
　
Groups Note: displays the user group to which the user belongs.
　
Grpck
　
Note: Use the/etc/group and/etc/gshadow file content to synchronize or create/etc/gshadow. If/etc/gshadow does not exist, create it;
　
Grpunconv Note: Use the/etc/group and/etc/gshadow file content to synchronize or create/etc/group, and then delete the gshadow file.