passwd

Additional Notes

passwd changes a user's password. Normal users can change their own password. Root can change passwords and password status for other accounts.

Password hashes are normally stored in /etc/shadow, not directly in /etc/passwd.

Syntax

passwd [options] [user]

Parameters

• options: Flags that change how passwd behaves.
• user: User account affected by the command.
• group: Group account affected by the command.
• file: File or directory whose ownership, mode, or access policy is being changed.

Common Options

• -l USER: Lock a user's password.
• -u USER: Unlock a user's password.
• -d USER: Delete a user's password.
• -S USER: Show password status.
• -e USER: Expire a password so it must be changed at next login.
• -n DAYS: Set minimum password age.
• -x DAYS: Set maximum password age.
• -w DAYS: Set warning days before expiration.

Examples

passwd

Change your own password.

sudo passwd rani

Change another user's password.

sudo passwd -S rani

Show password status.

sudo passwd -l guest

Lock an account password.

sudo passwd -e rani

Force a password change at next login.

Practical Notes

• Use strong, unique passwords.
• Locking a password is not always the same as disabling every possible login method.
• SSH key login may still work depending on configuration.
• Use chage for detailed password aging policy.
• Be careful with passwd -d; passwordless accounts are risky.