passwd(4)                                               passwd(4)



NAME
     passwd - password file

SYNOPSIS
     passwd

DESCRIPTION
     passwd contains the following information for each user on
     the system:

          name Specifies the user's login name; contains no
               uppercase characters and must contain more than
               eight characters.

          password
               Specifies the user's encrypted password as well as
               aging information.

          numeric-user-ID
               Specifies the user's ID in the system and it must
               be unique.  If zero, an account with root
               privileges is created. The highest value that can
               be used for a user ID is 60000.  The upper limit
               is established in the file /usr/include/limits.h.

          numeric-group-ID
               Specifies the number of the group that the user
               belongs to.

          real-name
               Specifies detailed information about the user,
               such as the user's place of work, office and home
               phone numbers, and so on.  For historical reasons,
               this field is called the ``GCOS'' field.

          default-working-directory
               Specifies the directory that users are positioned
               in after logging in to the system.  This is known
               as the ``home'' directory.

          shell
               Specifies the program to use as the shell when the
               user logs in.

     The user's real-name field can contain an ampersand (&),
     meaning ``insert the login name.''

     The password file is an ASCII file.  Each field within each
     user's entry is separated from the next by a colon.  The
     entry for each user is separated from the next by a newline.
     If the password field is null, no password is demanded; if
     the shell field is null, /bin/sh is used.



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passwd(4)                                               passwd(4)



     This file resides in directory /etc.  Because of the
     encrypted passwords, it has general read permission and can
     be used, for example, to map numeric user IDs to names.

     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 or her encrypted password in the password file
     is followed by a comma and a non-null string of characters
     from the list just given.  (Such a string must be introduced
     in the first instance by the user logged in as root.)

     The first character of the age, such as M, denotes the
     maximum number of weeks for which a password is valid.  A
     user who attempts to login after his or her password has
     expired will be forced to supply a new one.  The next
     character, such as m, denotes the minimum period in weeks
     that must expire before the password can 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 listed earlier (that is, / = 1 week; z = 63 weeks).
     If m = M = 0 (derived from the string . or ..), the user
     will be forced to change his or her password the next time
     he or she logs in (and the ``age'' will disappear from his
     or her entry in the password file).  If m > M (signified,
     for example, by the string ./), only the user logged in as
     root will be able to change the password.

     The passwd file can also contain a line beginning with a
     plus sign (+), which means that entries from the Network
     Information Service (NIS, formerly called ``Yellow Pages'')
     should be incorporated.  There are three styles of +
     entries:  alone, + means to insert the entire contents of
     the NIS password file at that point; +name means to insert
     the entry (if any) for name from the NIS password file at
     that point; +@name means to insert the entries for all
     members of the network group name at that point.  If a +
     entry has a non-null password, directory, GCOS, or shell
     field, it will override the contents of the NIS password
     file.  The numeric user ID and group ID fields cannot be
     overridden.

EXAMPLES
     Here is a sample /etc/passwd file:

        root:q.mJzTnu8icF.:0:10:God:/:/bin/csh
        ja:6k/7KCFRPNVXg:508:10:Jerry Asher:/usr2/ja:/bin/csh
        +melissa:
        +@documentation:no-login:



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passwd(4)                                               passwd(4)



        +:::Guest

     In this example, there are specific entries for users root
     and ja, in case NIS is out of order.  The user melissa will
     have her password entry in NIS incorporated without change;
     anyone in the netgroup documentation will have his or her
     password field disabled, and anyone else will be able to log
     in with his or her usual password, shell, and home
     directory, but with a GCOS field of Guest.

     Appropriate precautions must be taken to lock the
     /etc/passwd file against simultaneous changes if it is to be
     edited with a text editor; vipw does the necessary locking.

FILES
     /etc/passwd
          File containing user information

SEE ALSO
     crypt(3), getpwent(3), group(4)

     login(1), passwd(1) in A/UX Command Reference

     vipw(1M) in A/UX System Administrator's Reference































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