Provided by: passwd_4.1.4.2-1ubuntu3_i386 bug

crypt(3).
crypt(3), for instance ! or *, the user will not be able to use a unix

date of last password change

    The date of the last password change, expressed as the number of days
    since Jan 1, 1970.

    The value 0 has a special meaning, which is that the user should change
    her pasword the next time she will log in the system.

    An empty field means that password aging features are disabled.

minimum password age

    The minimum password age is the number of days the user will have to wait
    before she will be allowed to change her password again.

    An empty field and value 0 mean that there are no minimum password age.

maximum password age

    The maximum password age is the number of days after which the user will
    have to change her password.

    After this number of days is elapsed, the password may still be valid. The
    user should be asked to change her password the next time she will log in.

    An empty field means that there are no maximum password age, no password
    warning period, and no password inactivity period (see below).

    If the maximum password age is lower than the minimum password age, the
    user cannot change her password.

password warning period

    The number of days before a password is going to expire (see the maximum
    password age above) during which the user should be warned.

    An empty field and value 0 mean that there are no password warning period.

password inactivity period

    The number of days after a password has expired (see the maximum password
    age above) during which the password should still be accepted (and the
    user should update her password during the next login).

    After expiration of the password and this expiration period is elapsed, no
    login is possible using the current users password. The user should
    contact her administrator.

    An empty field means that there are no enforcement of an inactivity
    period.

account expiration date

    The date of expiration of the account, expressed as the number of days
    since Jan 1, 1970.

    Note that an account expiration differs from a password expiration. In
    case of an acount expiration, the user shall not be allowed to login. In
    case of a password expiration, the user is not allowed to login using her
    password.

    An empty field means that the account will never expire.

    The value 0 should not be used as it is interpreted as either an account
    with no expiration, or as an expiration on Jan 1, 1970.

reserved field

    This field is reserved for future use.

       /etc/passwd

       /etc/shadow

       /etc/shadow-
           Backup file for /etc/shadow.

           Note that this file is used by the tools of the shadow toolsuite,
           but not by all user and password management tools.

       chage(1), login(1), passwd(1), passwd(5), pwck(8), pwconv(8),
       pwunconv(8), su(1), sulogin(8).

                                  09/03/2010                         shadow(5)