Tech Tutorial: Manage Users and Groups on RHEL #
Introduction #
In Red Hat Enterprise Linux (RHEL), managing users and groups is a fundamental task for system administrators. This tutorial aims to provide a comprehensive guide on how to create, delete, and modify local user accounts in RHEL. This is particularly valuable for those preparing for the Red Hat Certified System Administrator (RHCSA) exam, as it covers essential exam objectives related to user management.
Step-by-Step Guide #
1. Creating a New User #
To create a new user in RHEL, you use the useradd
command. This command allows you to create a new user account that users can use to log in and access the system.
Syntax and Options #
useradd [options] USERNAME
USERNAME
is the name of the user to be created.
Here are some commonly used options with useradd
:
-c
: Comment field, generally used for the full name of the user.-d
: Home directory for the user.-m
: Create the user’s home directory if it does not exist.-s
: Default shell for the user.
Example: #
sudo useradd -c "John Doe" -d /home/johndoe -m -s /bin/bash johndoe
This command creates a new user named johndoe
, with a home directory /home/johndoe
, and the default shell set to /bin/bash
.
2. Setting or Changing a User’s Password #
After creating a user, set the user’s password using the passwd
command.
Syntax #
passwd USERNAME
Example: #
sudo passwd johndoe
You will be prompted to enter and confirm the new password.
3. Modifying an Existing User #
To modify an existing user, use the usermod
command. This is useful for changing user details such as the user’s login name, home directory, or shell.
Syntax and Options #
usermod [options] USERNAME
Some options for usermod
include:
-l
: New login name for the user.-d
: New home directory for the user.-m
: Move the contents from the user’s current directory to the new directory.-s
: New login shell for the user.
Example: #
sudo usermod -l johnnew -d /home/johnnew -m -s /bin/zsh johndoe
This command changes johndoe
’s username to johnnew
, home directory to /home/johnnew
, moves the old contents to the new directory, and changes the shell to /bin/zsh
.
4. Deleting a User #
To delete a user, use the userdel
command.
Syntax and Options #
userdel [options] USERNAME
-r
: Removes the user along with the user’s home directory and mail spool.
Example: #
sudo userdel -r johnnew
This command deletes the user johnnew
and removes the home directory along with the mail spool.
Detailed Code Examples #
Let us create a user, modify them, and then delete them:
# Create a user
sudo useradd -c "Example User" -m -s /bin/bash exampleuser
# Set user password
sudo passwd exampleuser
# Modify the user
sudo usermod -l newexampleuser -d /home/newexampleuser -m exampleuser
# Delete the user
sudo userdel -r newexampleuser
Conclusion #
In this tutorial, we’ve covered how to manage users and groups on RHEL, focusing on creating, modifying, and deleting user accounts. These operations form the backbone of system administration and are crucial for anyone preparing for the RHCSA exam. With the commands and examples provided, you should be well-prepared to handle user management tasks on a RHEL system.