How to Change User Password in Linux | passwd Command

Securing user accounts is a fundamental aspect of maintaining a robust and secure Linux system. One essential task is changing user passwords regularly to prevent unauthorized access. The passwd command in Linux provides a straightforward and effective way to modify user passwords. This article will guide you through the process of changing user passwords using the passwd command, offering insights into its various options and best practices.

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] 

Here,

[options] = include various parameters to customize the password-changing process.

[username] = the target user account for which you want to change the password.

Options Available in `passwd` Command in Linux

1. How to Change User Password in Linux

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

Step 1: Open a terminal on your Linux system.

Step 2: Type the following command and press Enter:

passwd 

how to change user password in Linux

• If you are not the root user, you will be prompted to enter your current password to proceed.
• You will then be prompted to enter the new password. Type the new password and press Enter.
• Retype the new password when prompted to confirm.
• The password for the specified user account is now changed.

Note: Linux does not display any characters on the screen while you type the password for security reasons.

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:

Step 1: Open a terminal on your Linux system.

Step 2: Type the following command and press Enter:

passwd user1 

How to change another user password

• If you are not the root user, you may be prompted to enter your current password to proceed.
• You will then be prompted to enter the new password. Type the new password and press Enter. Linux does not display any characters on the screen while you type the password for security reasons.
• Retype the new password when prompted to confirm.
• The password for the user “john” is now changed.

Note: sudo can be used to invoke root privileges by normal users, and can change the password for root itself. This is particularly helpful when a user is member of admin group (holds a position in sudoers list (/etc/sudoers) and can use commands with sudo) and the root password is not set, which is case with many common distributions of linux.

sudo passwd root 

3. How to Change the User Password Forcely

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

passed -e user1

changing the user password forcefully

This immediately expires the user’s password, requiring them to change it the next time they log in.

4. How to Lock and Unlock User Account in Linux

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

To lock the account:

passwd -l user2

The password for the user “user2” is now locked, preventing login.

To unlock the account:

passwd -u user2

The password for the user “user2” is now unlocked, allowing login again.

5. How to Set Password Expiry

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

passwd -x 30 user3

This sets a maximum password age of 30 days for the user “user3”

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:

user1:$6$x8wAJRpP$EWC97sXW5tqac10Q2TQyXkR.1l1jdK4VLK1pkZKmA2mbA6UnSGyo94Pis074viWBA3sVbkCptSZzuP2K.y.an/:17887:0:99999:7:::

Processing in passed Command

• field 1: User name.
• field 2: Encrypted Password.
• field 3: Number of days since January 1, 1970 to when the password was last changed.
• field 4: Minimum number of days for which password can not be changed. (value 0 means it can be changed anytime).
• field 5: Number of days after password must be changed. (value 99999 means that the password never expires).
• field 6: Number of days to warn user for expiring password.
• field 7: Number of days after password expires that the account is disabled.
• field 8: The number of days from January 1, 1970 to the date when an account was disabled.
• field 9: This field is reserved for some possible future use.

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.

How to Change User Password in Linux | passwd Command – FAQs

How to Change a User’s Password in Linux?

To change a user’s password in Linux, the passwd command is commonly used. If you are a regular user wanting to change your own password, simply type:

passwd

You will be prompted to enter your current password for verification, followed by the new password twice (the second time for confirmation).

If you are an administrator (or have sudo privileges) and need to change the password for another user, you specify the username after the passwd command:

sudo passwd username

This will prompt you to enter a new password for the specified user, without needing to enter the current password.

What is the passwd command used for besides changing passwords?

Besides changing user passwords, the passwd command also allows for managing various aspects of users’ passwords, including:

• Setting Password Expiry Information: Administrators can use passwd to change the password aging/expiry policy.
• Locking and Unlocking User Accounts: passwd can disable or enable user accounts by locking or unlocking them.
• Changing Account or Password Expiry Dates: It allows setting or changing the date when a user’s account will be disabled or when the password must be changed.

How to force a user to change their password at next login?

To force a user to change their password at the next login, use the passwd command with the --expire option:

sudo passwd --expire username

This command effectively expires the password immediately, prompting the user to set a new password the next time they log in.

What are some common options for the passwd command?

The passwd command includes several options that provide control over user passwords and accounts:

• -d: Deletes a password, making the account passwordless, subject to system policy.
• -e, –expire: Forces the user to change their password at the next login.
• -l, –lock: Locks the user account.
• -u, –unlock: Unlocks the user account.
• -n, –mindays DAYS: Sets the minimum number of days between password changes to DAYS.
• -x, –maxdays DAYS: Sets the maximum number of days the password is valid.
• -w, –warndays DAYS: Sets the number of days a user is warned before their password expires.
• -i, –inactive INACTIVE: Sets the number of days after a password expires until the account is permanently disabled.

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Article Tags :

• Linux-Unix
• linux-command
• Linux-system-commands