passwd - password file




     The file /etc/passwd is a local source of information  about
     users'  accounts.  The password file can be used in conjunc-
     tion with other password  sources,  such  as  the  NIS  maps
     passwd.byname  and  passwd.bygid  and the NIS+ table passwd.
     Programs use the getpwnam(3C) routines to access this infor-

     Each passwd entry is a single line of the form:



           is the user's login name. It is recommended that  this
           field conform to the checks performed by pwck(1M).

           is an empty field. The encrypted password for the user
           is in the corresponding entry in the /etc/shadow file.
           pwconv(1M) relies on a special value  of  'x'  in  the
           password  field  of  /etc/passwd. If this value of 'x'
           exists in the  password  field  of  /etc/passwd,  this
           indicates that the password for the user is already in
           /etc/shadow and should not be modified.

     uid   is the user's unique numerical ID for the system.

     gid   is the unique numerical ID of the group that the  user
           belongs to.

           is the user's real name,  along  with  information  to
           pass  along  in  a mail-message heading. (It is called
           the  gcos-field  for  historical  reasons.)  An  ``&''
           (ampersand)  in  this  field stands for the login name
           (in cases where the login name  appears  in  a  user's
           real name).

           is the pathname to the directory in which the user  is
           initially positioned upon logging in.

           is the user's initial shell program. If this field  is
           empty, the default shell is /usr/bin/sh.

     The maximum value of the uid and gid fields  is  2147483647.
     To  maximize interoperability and compatibility, administra-
     tors are recommended to assign users a  range  of  UIDs  and
     GIDs below 60000 where possible.

     The password file is an ASCII file.  Because  the  encrypted
     passwords  are  always  kept in the shadow file, /etc/passwd
     has general read permission on all systems and can  be  used
     by  routines  that  map  between numerical user IDs and user

     Blank lines are treated as malformed entries in  the  passwd
     file and cause consumers of the file , such as getpwnam(3C),
     to fail.

     Previous releases used a password entry beginning with a `+'
     (plus  sign)  or `-' (minus sign) to selectively incorporate
     entries from NIS maps for password. If still required,  this
     is   supported   by   specifying   ``passwd  :  compat''  in
     nsswitch.conf(4). The "compat" source might not be supported
     in future releases. The preferred sources are files followed
     by the identifier of a name service, such as  nis  or  ldap.
     This  has the effect of incorporating the entire contents of
     the name service's passwd database after the passwd file.


     Example 1: Sample passwd file

     The following is a sample passwd file:

     fred:6k/7KCFRPNVXg:508:10:& Fredericks:/usr2/fred:/bin/csh

     and the sample password entry from nsswitch.conf:

     passwd: files nisplus

     In this example, there are specific entries for  users  root
     and  fred to assure that they can login even when the system
     is running single-user. In  addition,  anyone  in  the  NIS+
     table  passwd  will  be able to login with their usual pass-
     word, shell, and home directory.

     If the password file is:

     fred:6k/7KCFRPNVXg:508:10:& Fredericks:/usr2/fred:/bin/csh
     and the password entry from nsswitch.conf is:

     passwd: compat

     then all the entries listed  in  the  NIS  passwd.byuid  and
     passwd.byname  maps  will  be effectively incorporated after
     the entries for root and fred.






     chgrp(1),   chown(1),   finger(1),   groups(1),    login(1),
     newgrp(1),    nispasswd(1),   passwd(1),   sh(1),   sort(1),
     chown(1M),    domainname(1M),    getent(1M),    in.ftpd(1M),
     passmgmt(1M),  pwck(1M),  pwconv(1M),  su(1M),  useradd(1M),
     userdel(1M), usermod(1M),  a64l(3C),  crypt(3C),  getpw(3C),
     getpwnam(3C),    getspnam(3C),    putpwent(3C),    group(4),
     hosts.equiv(4),  nsswitch.conf(4),  shadow(4),   environ(5),

     System Administration Guide: Basic Administration

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