passwd(1)                                               passwd(1)



     NAME
          passwd - change login password

     SYNOPSIS
          passwd [name]

     DESCRIPTION
          This command changes (or installs) a password associated
          with the login name.

          Ordinary users may change only the password which
          corresponds to their login name.

          passwd prompts ordinary users for their old password, if
          any.  It then prompts for the new password twice.  The first
          time the new password is entered passwd checks to see if the
          old password has aged sufficiently.  If aging is insuffi-
          cient, the new password is rejected and passwd terminates;
          see passwd(4).

          Assuming aging is sufficient, a check is made to ensure that
          the new password meets construction requirements. When the
          new password is entered a second time, the two copies of the
          new password are compared.  If the two copies are not ident-
          ical, the cycle of prompting for the new password is repeat-
          ed for at most two more times.

          Passwords must meet the following requirements:

               Each password must have at least six characters.  Only
               the first eight characters are significant.

               Each password must contain at least two alphabetic
               characters (uppercase or lowercase) and at least one
               numeric or special character.

               Each password must differ from the user's login name
               and any reverse or circular shift of that login name.
               For comparison purposes, an uppercase letter and its
               corresponding lowercase letter are equivalent.

               New passwords must differ from the old by at least
               three characters.  For comparison purposes, an upper-
               case letter and its corresponding lowercase letter are
               equivalent.

          One whose effective user ID is zero is called a superuser;
          see id(1), and su(1).  Superusers may change any password;
          hence, passwd does not prompt superusers for the old pass-
          word.  Superusers are not forced to comply with password ag-
          ing and password construction requirements.  A superuser can
          create a null password by entering a carriage return in



     April, 1990                                                     1

     passwd(1)                                               passwd(1)



          response to the prompt for a new password.

     EXAMPLES
               passwd

          will give the response

               Changing password for <username>

          and will then prompt for your present password and for the
          new password (twice).

     FILES
          /bin/passwd
          /etc/passwd

     SEE ALSO
          chsh(1), login(1), id(1), su(1), crypt(3C), passwd(4).





































     2                                                     April, 1990