Essential System Administration, 3rd Edition

Managing User Accounts

In this section, we will consider the processes of adding, configuring, and removing user accounts on Unix systems.

Adding a New User Account

Adding a new user to the system involves the following tasks:

• Assign the user a username, a user ID number, and a primary group, and decide which other groups she should be a member of (if any). Enter this data into the system user account configuration files.

• Assign a password to the new account.

• Create a home directory for the user.

• Place initialization files in the user’s home directory.

• Use chown and/or chgrp to give the new user ownership of his home directory and initialization files.

• Set other user account parameters appropriate for your system (possibly including password aging, account expiration date, resource limits, and system privileges).

• Add the user to any other facilities in use as appropriate (e.g., the disk quota system, mail system, and printing system).

• Grant or deny access to additional system resources as appropriate, using file protections or the resources’ own internal mechanisms (e.g., the /etc/ftpusers file controls access to the ftp facility).

• Perform any other site-specific initialization tasks.

• Test the new account.

We will consider each of these steps in detail in this section. This discussion assumes that you’ll be adding a user by hand. Few people actually do this anymore, but it is important to understand the whole process even if you use a tool that automates a lot of it for you. The available tools ...