passwd

changes user passwords

TLDR

Change your password

$ passwd

Change another user's password (root)

$ passwd [username]

Lock a user account

$ passwd -l [username]

Unlock a user account

$ passwd -u [username]

Force password change on next login

$ passwd -e [username]

Set password to expire in days

$ passwd -x [90] [username]

Show password status

$ passwd -S [username]

Delete user's password (passwordless)

$ passwd -d [username]

passwd changes user passwords. When run without arguments by a regular user, it prompts for the current password and then allows setting a new one. Root can change any user's password without knowing the old one.The tool enforces password policies including minimum length, complexity requirements, and history restrictions. These policies are configured in /etc/login.defs and PAM configuration.passwd also manages password aging, allowing administrators to force periodic password changes, expire passwords, and lock/unlock accounts.

PARAMETERS

-l, --lock

Lock the account password.

-u, --unlock

Unlock the account password.

-d, --delete

Delete password (make passwordless).

-e, --expire

Force password change on next login.

-n days, --mindays days

Minimum days between changes.

-x days, --maxdays days

Maximum days before change required.

-w days, --warndays days

Days before expiry to warn user.

-i days, --inactive days

Days after expiry before account disabled.

-S, --status

Show password status information.

-a, --all

With -S, show status for all users.

--stdin

Read password from stdin (non-interactive).

INSTALL

sudo apt install passwd

sudo pacman -S shadow

sudo apk add shadow

sudo zypper install shadow

nix profile install nixpkgs#shadow

CAVEATS

Requires root to change other users' passwords. PAM modules may enforce additional password requirements. Locked accounts can still be accessed via SSH keys. Password policies vary by system configuration.

HISTORY

passwd has been part of Unix since the earliest versions, dating back to Version 1 Unix at Bell Labs in 1971. The password file originally contained hashed passwords directly, but modern systems use shadow passwords (/etc/shadow) for security, introduced in SunOS in the 1980s.