Users and Groups

Linux Tutorials - Herong's Tutorial Examples

∟Users and Groups

This chapter provides introductions and tutorial on user and group management. Topics include commands to add and remove groups; commands to associate users with primary and supplementary groups; commands to file group ownership and group access permissions; commands to add and delete users; run 'sudo' command to gain 'root' permision.

Manage User Groups

Group Access Permissions on Files

"sudo" Command and Privilege

"adduser/usermod/userdel" - Commands to Manage Users

System Users and Groups

Add Users and Groups Manually

Takeaways:

Use "groupadd" command to add a new explicitly.
Use "usermod -g" command to change user's primary group.
Use "gpasswd -a" command to assign supplementary group memership to a user.
Use "getent group" command to view supplementary group members of a given group.
Use "id" command to view primary group and supplementary groups of a given user.
Use "chgrp" command to change group ownership of a given file.
Use "chmod g=" command to change group access permissions of a given file.
Use "wheel" or "sudo" group to grant "sudo" privilege.
Use "sudo" command gain "root" permission for a given sub-command.
Use "adduser" command to add a new user.
Use "passwd" command to reset a user's password.
Use "userdel" command to delete a user's login access and home directory.
Read "/etc/passwd" file to see user information.
Read "/etc/shadow" file to see user's password information.