Part III Managing Your System: Administering Users and Groups
Christine Bresnahan, Richard A. Blum · 2019
This chapter covers administering the access controls Linux uses to check a user's credentials and permit or deny access to the system. Adding and modifying user account credentials, which includes usernames, account information, and passwords, is an important (but tedious) part of system administration. In addition, you need to know how to delete these credentials, when warranted. Managing the user account and group memberships for a Linux system involves many critical pieces. You need to understand the account creation process as well as the files used. You must grasp the entire mechanism for times when troubleshooting authentication issues for a particular user is necessary. In addition, being able to use various utilities for identifying various users can assist. User accounts may be gathered together into various groups, which provide additional access. These group memberships are part of the authorization in which users can gain entry into various files and directories. Knowing the key areas of group administration is critical for proper Linux system management. Besides protecting your system through properly authenticated and authorization user and group mechanisms, you can also shield your filesystems from overuse. In particular, setting up filesystem user and group quotas will provide an additional layer of protection.