passwd

passwd is used to change the password of a user account 

$ passwd [OPTION] [USER]

Useful Options / Examples

A user can run passwd to change their own password and a superuser can use passwd to change another user’s password.

passwd

$ passwd
Changing password for [USER].
(current) UNIX password:
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Break it down
  • passwd with no options or user specified will change the password of the user running the command.

sudo passwd [OTHER_USER]

$ sudo passwd other
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
Break it down
  • If you have superuser privileges, you can modify the password of other users.
  • Prefix the command with sudo to run it as a superuser.
  • This will allow you to change the password for another user and not be prompted for their password.

sudo passwd -S [OTHER_USER]

$ sudo passwd -S other
other P 10/17/2017 0 99999 7 -1
Break it down
  • The -S option displays password information for a given user.
  • The 7 fields correspond to the following values:
    1. User’s login name
    2. Password usability (‘L’ if locked, ‘NP’ if there is no password, ‘P’ if there is a usable password)
    3. Date of last password change
    4. Minimum password age (days)
    5. Maximum password age (days)
    6. Warning period before a required password change
    7. Number of days to change a password after the maximum password age is reached

sudo passwd -l [OTHER_USER]

$ sudo passwd -l other
passwd: password expiry information changed.
$ sudo passwd -S other
other L 10/17/2017 0 99999 7 -1
Break it down
  • The -l option allows a superuser to lock another user’s account by disabling their password.
  • To have their password unlocked, a user will need to contact a superuser to unlock it.
  • User’s who have had their password locked can still login using other authentication methods (SSH).

sudo passwd -u [OTHER_USER]

$ sudo passwd -u other
passwd: password expiry information changed.
$ sudo passwd -S other
other P 10/17/2017 0 99999 7 -1
Break it down
  • The -u option allows a superuser to unlock another user’s account by enabling their previous password.

sudo passwd -d [OTHER_USER]

$ sudo passwd -d other
passwd: password expiry information changed.
$ sudo passwd -S other
other NP 10/17/2017 0 99999 7 -1
Break it down
  • The -d option allows a superuser to delete another user’s password.
  • This will disable logins for a users account, without disabling their account completely.

sudo passwd -e [OTHER_USER]

$ sudo passwd -e other
passwd: password expiry information changed.
$ sudo passwd -S other
other P 01/01/1970 0 99999 7 -1
Break it down
  • The -e option allows a superuser to expires another user’s account which will require that user to change their password.