Linux passwd Command with Practical Examples

Introduction

In this lab, we will explore the Linux passwd command, which is used to change user passwords. We will learn how to check the current user's password status, change the password for a specific user account, and reset the password for a user account when the user has forgotten their password. The passwd command is a fundamental tool for managing user accounts and security in a Linux system.

The lab covers the following steps:

• Understanding the passwd command
• Changing user password
• Resetting forgotten password

Linux Commands Cheat Sheet

Understanding the passwd Command

In this step, we will explore the Linux passwd command, which is used to change user passwords. The passwd command is a fundamental tool for managing user accounts and security in a Linux system.

First, let's check the current user's password status:

passwd -S labex

Example output:

labex PS 2023-04-12 0 0 99999 7 -1 (Password set, SHA512 crypt.)

This output shows that the labex user has a password set, and the password is encrypted using the SHA512 algorithm.

Now, let's change the password for the labex user:

sudo passwd labex

You will be prompted to enter the new password twice:

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

The passwd command updates the user's password in the /etc/shadow file, which stores the encrypted passwords for all user accounts on the system.

Changing User Password

In this step, we will learn how to change the password for a specific user account in the Linux system.

First, let's create a new user account named newuser:

sudo useradd -m newuser

Now, let's change the password for the newuser account:

sudo passwd newuser

You will be prompted to enter the new password twice:

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

The passwd command updates the user's password in the /etc/shadow file, which stores the encrypted passwords for all user accounts on the system.

To verify the password change, you can switch to the newuser account and try to log in:

su - newuser

You should be able to log in with the new password you just set.

Resetting Forgotten Password

In this step, we will learn how to reset the password for a user account when the user has forgotten their password.

First, let's create another user account named forgottenuser:

sudo useradd -m forgottenuser

Now, let's try to reset the password for the forgottenuser account:

sudo passwd forgottenuser

You will be prompted to enter the new password twice:

Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

The passwd command updates the user's password in the /etc/shadow file, which stores the encrypted passwords for all user accounts on the system.

To verify the password reset, you can switch to the forgottenuser account and try to log in:

su - forgottenuser

You should be able to log in with the new password you just set.

Summary

In this lab, we learned how to use the Linux passwd command to manage user passwords. We started by understanding the passwd command and checking the current user's password status. Then, we learned how to change the password for a specific user account, and finally, we explored the process of resetting a forgotten password. The lab provided practical examples and step-by-step instructions, ensuring a comprehensive understanding of password management in a Linux system.

Linux Commands Cheat Sheet