Linux Users and user groups

Linux is a multi-user multi-task time-sharing operating system.

Linux users have only two levels: root and non-root users. The Linux system defaults to the built-in root user and some non-root users, such as NOBODY,ADMIN,FTP.

User groups: Users can abstract the number of files that users can access at a higher level, so a user can combine different groups of users to create a unique

File access list, but also can be staggered between different users, in a methodical manner. A good balance is achieved between user collaboration and privacy protection. A user

Should be at least within a user group.

View all user lists through the/etc/passwd file

View all user groups through the/etc/group file

Add a user, delete a user, modify a user

Using sudo as a pretext for identity

Use su to switch between temporary users

WhoAmI and who Am I

Linux Users and user groups