Efficient User Session Management in Linux using sudo

User management is an important aspect of maintaining an efficient and secure Linux server. One essential tool for managing user sessions and permissions in Linux is sudo. sudo stands for “superuser do” and allows authorized users to execute commands as another user, usually the root or superuser. To switch users in Linux, use the command “su”, while replacing the username of the account you want to switch.

In this post, we will discuss how to manage user sessions in Linux using sudo, including configuring and customizing sudo for specific needs. If you are new to Linux this post is helpful to you regarding how you can create and switch users in Linux using the command line.

Understanding sudo command

Sudo is a command that allows users to run programs with the privileges of another user, by default, the superuser. This is useful for tasks that require administrative privileges, such as installing software, deleting files, and managing user accounts.

How does sudo work?

It is important for beginners to understand how sudo works When you run a sudo command:

1. The system first checks the sudoers file to see if you are allowed to run that command with elevated privileges.
2. If you are, the system will prompt you for your password.
3. Once you have entered your password, the system will run the command as root.

Installation and configuration

To manage user sessions with sudo, you first need to check that sudo is installed on your Linux system. Most distributions installed sudo by default, but you can install it if it’s not present. For example, on Debian-based like the Ubuntu servers, you can type the following command:

apt install sudo

To install in Fedora or CentOS system, you can type the following command:

yum install sudo 

After installing you can confirm by typing the following command.

sudo -h

As the picture shows below the usage of sudo:

Sudo will read the /etc/sudoers file and check whether the user has sudo access permission. When you use sudo for the first time in a session, you will be requested for the user password, and the command will be run as root. You can also modify the configuration file by using the command:

sudo visudo

This will open the /etc/sudoers file. Add the following code to add a user with full sudo privileges:

[username] ALL=(ALL:ALL) ALL

Managing user sessions with sudo

We use the su command combined with sudo. By combining the sudo and su commands, you can switch to a different user session with elevated privileges.

Using the sudo su command

The su command (short for substitute or switch user) allows you to run commands with another user’s privileges, by default the root user. The sudo command (short for the superuser do) allows you to run commands as another user, by default the root user.

To change your user session using sudo su, follow these steps:

1. Open a terminal window.
2. Type the following command:

sudo su username

Replace the username with the name of the user you want to switch to. For example, to switch to the root user, you would type:

sudo su - root

3. Enter your password when prompted
4. You will now be logged in as the specified user.

To log out another user, you can use the following command:

sudo pkill -u username

This will terminate all of the processes running under the specified user account. The user will then be logged out.

To kill a specific process belonging to another user, you can use the following command:

sudo killall process_name

This will terminate all of the processes with the specified name.

To change the password of another user, you can use the following command:

sudo passwd username

This will prompt you to enter the new password for the specified user account.

Be careful when using sudo su to switch to a different user session. With elevated privileges, you can make changes to the system that could potentially cause damage. Only switch to a different user session if you are sure that you need to, and be careful about the commands that you run.

Best practices

Here are some best practices for using sudo:

• Only use sudo when necessary.
• Use the least privilege principle, that you should only grant yourself the privileges that you need to complete the task at hand.
• Avoid running sudo commands from scripts or cron jobs. This is because if your script or cron job is compromised.
• Keep the sudoers file secure. The sudoers file contains a list of all the users and groups that are allowed to use sudo, as well as the commands that they are allowed to run.

Conclusion

sudo can be used to manage user sessions and run commands with elevated privileges. To understand how sudo works and how to configure it, you can use sudo to improve the security and efficiency of your Linux system. It is important to use sudo wisely and to follow the best practices outlined above to keep your system secure.