PASSWD(4)            INTERACTIVE UNIX System            PASSWD(4)



          NAME
               passwd - password file

          DESCRIPTION
               passwd contains for each user the following information:

                    login name
                    password and (optional) aging
                    numerical user ID
                    numerical group ID
                    GCOS job number, box number, optional GCOS user ID
                    initial working directory
                    program to use as shell

               This is an ASCII file.  Each field within each user's entry
               is separated from the next by a colon.  The GCOS field is
               used only when communicating with that system, and in other
               installations can contain any desired information.  Each
               user is separated from the next by a new-line.  If the shell
               field is null, /bin/sh is used.

               This file has user login information, and has general read
               permission.  It can therefore be used, for example, to map
               numerical user IDs to names.

               The password field consists of the character x if there is a
               /etc/shadow file.  If /etc/shadow does not exist and the
               login does have a password, this field will contain an
               encrypted copy of the password.  This field remains only for
               compatibility reasons when /etc/shadow exists.

               The encrypted password consists of 13 characters chosen from
               a 64-character alphabet (., /, 0-9, A-Z, a-z) except when
               the password is null, in which case the encrypted password
               is also null.  Password aging is effected for a particular
               user if his encrypted password in the password file is fol-
               lowed by a comma and a non-null string of characters from
               the above alphabet.  (Such a string must be introduced in
               the first instance by the super-user.)

               The first character of the age, M say, denotes the maximum
               number of weeks for which a password is valid.  A user who
               attempts to login after his password has expired will be
               forced to supply a new one.  The next character, m say,
               denotes the minimum period in weeks that must expire before
               the password may be changed.  The remaining characters
               define the week (counted from the beginning of 1970) when
               the password was last changed.  (A null string is equivalent
               to zero.)  M and m have numerical values in the range 0-63
               that correspond to the 64-character alphabet shown above
               (i.e., / = 1 week; z = 63 weeks).  If m = M = 0 (derived
               from the string . or ..)  the user will be forced to change
               his password the next time he logs in (and the ``age'' will


          Rev.                                                       Page 1

          PASSWD(4)            INTERACTIVE UNIX System            PASSWD(4)



               disappear from his entry in the password file).  If m > M
               (signified, for example, by the string ./) only the super-
               user will be able to change the password.

          FILES
               /etc/passwd
               /etc/shadow

          SEE ALSO
               getpwent(3C), group(4).
               login(1), passwd(1), and passwd(1M) in the INTERACTIVE UNIX
               System User's/System Administrator's Reference Manual.











































          Rev.                                                       Page 2