Basic Syntax of `passwd` in Linux

Understanding the `passwd` Command

The passwd command in Linux is a powerful tool that allows system administrators and users to manage password-related tasks. Its primary purpose is to change user passwords, but it offers additional functionalities such as updating password aging policies, unlocking accounts, and more....

Basic Syntax of `passwd` in Linux

passwd [options] [username]...

Options Available in `passwd` Command in Linux

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1. How to Change User Password in Linux

To change a user password using the passwd command, follow these steps:...

2. How to Change Another User’s Password in Linux

To change the password for a user other than the one currently logged in, you can use the following steps:...

3. How to Change the User Password Forcely

To force a user to change their password at the next login, use the following command:...

4. How to Lock and Unlock User Account in Linux

To lock or unlock a user account, use the following commands:...

5. How to Set Password Expiry

The -x option allows you to set the maximum number of days a password is valid. Example:...

Processing in passwd command:

Verify current user password : Once the user enters passwd command, it prompts for current user password, which is verified against the password stored in /etc/shadow file user. The root user can bypass this step and can directly change the password, so as the forgotten passwords may be recovered. Verify password aging information : In Linux, a user password can be set to expire after a given period of time. Also, a user can be prohibited to change his/her password for a period. This password aging information (and the password itself) is stored in a file /etc/shadow. Change the password : After authentication, the user is prompted to enter the new password and verify it by retyping the password. /etc/shadow file: The shadow file is a list of colon separated values with 9 fields, as shown below:...

Conclusion

In this article, we learned how to change user passwords in Linux using the passwd command. We explored its various features, from basic password changes to more advanced options like forcing updates, locking and unlocking accounts, and setting password expiry. By understanding these functionalities, Linux users and administrators can strengthen the security of their systems. Regularly updating passwords and following best practices play a crucial role in safeguarding against unauthorized access. The passwd command serves as a handy tool for managing these aspects, making it an essential part of maintaining a secure Linux environment....