Tech Tutorial: 107.1 Manage User and Group Accounts and Related System Permissions #
Introduction #
Linux is a multi-user system where managing users and groups is a fundamental aspect of system administration. This tutorial covers essential commands and procedures for managing user and group accounts on a Linux system. By the end, you will learn how to add, remove, suspend, and modify user accounts, along with managing group memberships.
Key Knowledge Areas: #
- User and group commands
- System files used to manage users and groups
Utilities: #
useradd
usermod
userdel
groupadd
groupmod
groupdel
passwd
chage
Step-by-Step Guide #
1. Adding User Accounts #
The useradd
command is used to create a new user account on a Linux system.
Code Example: #
# Add a new user with the default settings
sudo useradd johndoe
# Add a new user with a specific home directory and default shell
sudo useradd -d /home/johndoe -s /bin/bash johndoe
2. Modifying User Accounts #
To modify details of an existing user account, use the usermod
command.
Code Example: #
# Change the user's login name
sudo usermod -l johndoe_new johndoe
# Add a user to a supplementary group
sudo usermod -aG sudo johndoe
3. Deleting User Accounts #
Use the userdel
command to remove a user account from the system.
Code Example: #
# Delete a user account
sudo userdel johndoe
# Delete a user account and their home directory
sudo userdel -r johndoe
4. Managing Passwords #
The passwd
command is used to update a user’s password.
Code Example: #
# Set a password for a user
sudo passwd johndoe
# Lock a user's password
sudo passwd -l johndoe
# Unlock a user's password
sudo passwd -u johndoe
5. Changing User Account Expiry #
The chage
command is used to change the user password expiry information.
Code Example: #
# Set password expiry information for a user
sudo chage -E 2023-12-31 johndoe
# List password and account aging information
sudo chage -l johndoe
6. Adding Groups #
The groupadd
command allows you to create a new group.
Code Example: #
# Add a new group
sudo groupadd developers
7. Modifying Groups #
Modify group details using the groupmod
command.
Code Example: #
# Rename a group
sudo groupmod -n newdevelopers developers
8. Deleting Groups #
The groupdel
command is used to delete a group.
Code Example: #
# Delete a group
sudo groupdel developers
Conclusion #
Managing users and groups is a critical task for Linux system administrators. This tutorial provided a comprehensive guide on how to handle user and group accounts using various Linux commands. Mastery of these commands ensures effective user management and security on a Linux system. By practicing these commands, you can ensure your Linux system is both secure and organized.