passwd – Allows users to change their own passwords

The passwd command is a Linux utility that allows users to change their own passwords. It is a command-line interface tool that is used to modify the password of a user account on a Linux system. The passwd command is only available to the root user and users who have been granted permission to use it.

Overview

The passwd command is used to change the password of the current user or another user on the system. The syntax for the command is as follows:

passwd [options] [username]

Where username is the name of the user whose password you want to change. If no username is specified, the password for the current user will be changed.

When you run the passwd command, you will be prompted to enter the new password twice. The password will not be displayed on the screen as you type it.

Here are some examples of how to use the passwd command:

To change the password for the current user:

passwd

To change the password for a specific user:

passwd johndoe

To force the user to change their password at the next login:

passwd -e johndoe

To lock a user’s password:

passwd -l johndoe

To unlock a user’s password:

passwd -u johndoe

Options

The passwd command has several options that you can use to modify its behavior. Here is a table of the available options:

Option	Description
-a	This option is used to change the password for all users.
-d	This option is used to delete a user’s password.
-e	This option is used to force the user to change their password at the next login.
-h	This option is used to display the help message for the passwd command.
-k	This option is used to set the maximum number of days between password changes.
-l	This option is used to lock a user’s password.
-S	This option is used to display the status of a user’s password.
-u	This option is used to unlock a user’s password.

Troubleshooting tips

Here are some common issues that you may encounter when using the passwd command and how to troubleshoot them:

• If you receive an error message that says “passwd: Authentication token manipulation error”, it may be because the password file is not writable. Ensure that you have the necessary permissions to modify the password file.
• If you receive an error message that says “passwd: Authentication information cannot be recovered”, it may be because the password file is corrupted. Try restoring the password file from a backup.
• If you are unable to change your password, it may be because the password you are trying to set does not meet the system’s password complexity requirements. Ensure that your password meets the minimum length and complexity requirements.

Notes

• The passwd command should be used with caution, as it can potentially allow users to gain unauthorized access to a system if used improperly.
• It is recommended that users change their passwords regularly to ensure the security of their accounts.
• The passwd command is not available on all Linux distributions. Some distributions may use a different command or method for changing passwords.