View all users and all user groups in Linux

Groups
Groups gliethttp: view the group where the gliethttp user is located and the group members
Whoami

The/etc/group file contains all groups.
All usernames in the/etc/shadow and/etc/passwd Systems

1. Explanation of/etc/group;

/Etc/group

A file is a configuration file of a user group. It contains users and user groups, and shows which user group or user group the user belongs to, because a user can belong to one or more different user groups; same use

User groups have similar features. For example, if we add a user to the root user group, this user can browse the files in the root user's home directory.
The read/write execution permission is open. All users of the root user group can modify this file. If it is an executable file (such as a script), users of the root user group can also execute the file;

User Group features provide great convenience for system administrators in system management, but security is also worth noting. For example, a user has the most important content for system management, it is best to allow users to have independent user groups, or set the permissions of files under the user to be completely private. In addition, the root user group should not easily add normal users,

2. Detailed analysis of/etc/group content

The content of/etc/group includes the user group, user group password, GID, and user included in the user group. Each user group has a record. The format is as follows:

Group_name: passwd: GID: user_list

Each record in/etc/group has four fields:

Field 1: User Group name;

Field 2: User Group Password;

Third Field: GID

Field 4: User List. Each user is separated by a comma. This field can be blank. If the field is empty, it indicates that the user group is the user name of GID;

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