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NAME    [Toc]    [Back]

     passwd - format of the password file

DESCRIPTION    [Toc]    [Back]

     The master.passwd file, readable only by root,  consists  of
 records, one per user, containing ten colon (`:') separated fields.
     These fields are as follows:

           name      User's login name.
           password  User's encrypted password.
           uid       User's login user ID.
           gid       User's login group ID.
           class      User's  general  classification  (see   login.conf(5)).
           change    Password change time.
           expire    Account expiration time.
           gecos     General information about the user.
           home_dir  User's home directory.
           shell     User's login shell.

     The  publicly-readable  passwd  file  is  generated from the
     file by pwd_mkdb(8) and has the class,  change,  and  expire
fields removed.
     Also,  the encrypted password field is replaced by an asterisk (`*').

     The name field is the login used to access the computer  account, and the
     uid  field  is  the  number associated with it.  They should
both be unique
     across the system (and often  across  a  group  of  systems)
since they control
 file access.

     While it is possible to have multiple entries with identical
login names
     and/or identical user IDs, it is usually a mistake to do so.
     that  manipulate  these  files will often return only one of
the multiple
     entries, and that one by random selection.

     The login name may be up to 31 characters long.  For compatibility with
     legacy software, a login name should start with a letter and
     solely of letters, numbers, dashes and underscores.  The login name must
     never  begin  with a hyphen (`-'); also, it is strongly suggested that neither
 uppercase characters nor dots  (`.')  be  part  of  the
name, as this
     tends  to  confuse mailers.  No field may contain a colon as
this has been
     used  historically  to  separate  the  fields  in  the  user

     The  password  field  is the encrypted form of the password.
If the
     password field is empty, no password  will  be  required  to
gain access to
     the  machine.  This is almost invariably a mistake.  Because
     contains the encrypted user  passwords,  it  should  not  be
readable by anyone
 without appropriate privileges.

     Which  type of cipher is used to encrypt the password information depends
     on the configuration in login.conf(5).  It can be  different
for local and
     YP passwords.

     The group field is the group that the user will be placed in
upon login.
     Since this system supports multiple groups  (see  groups(1))
this field
     currently has little special meaning.

     The  class  field  is used by login(1) and other programs to
determine which
     entry in the login.conf(5) database should be used.

     The change field is the number in  seconds,  GMT,  from  the
epoch, until the
     password for the account must be changed.  This field may be
left empty
     to turn off the password aging feature.

     The expire field is the number in  seconds,  GMT,  from  the
epoch, until the
     account  expires.   This field may be left empty to turn off
the account
     aging feature.

     The gecos field normally contains comma (`,') separated subfields as follows:

           name    User's full name.
           office  User's office location.
           wphone  User's work phone number.
           hphone  User's home phone number.

     The  full name may contain an ampersand (`&'), which will be
replaced by
     the capitalized login name when the gecos field is displayed
or used by
     various programs such as finger(1), sendmail(8), etc.

     The  office  and  phone number subfields, if they exist, are
used by the
     finger(1) program and possibly by other applications.

     The user's home directory is the full UNIX path  name  where
the user will
     be placed on login.

     The shell field is the command interpreter the user prefers.
If there is
     nothing in the shell field, the Bourne  shell  (/bin/sh)  is

YP SUPPORT    [Toc]    [Back]

     If  YP  is active, the passwd file also supports standard YP
exclusions and
     inclusions, based on user names and netgroups.

     Lines beginning with a `-' (minus sign) are  entries  marked
as being excluded
  from any following inclusions, which are marked with
a `+' (plus

     If the second character of the line is a `@' (at sign),  the
operation involves
 the user fields of all entries in the netgroup specified by the
     remaining characters of the name field.  Otherwise, the  remainder of the
     name field is assumed to be a specific user name.

     The  `+'  token  may  also be alone in the name field, which
causes all users
     from the passwd.byname and passwd.byuid YP maps  to  be  included.

     If the entry contains non-empty uid or gid fields, the specified numbers
     will override the information retrieved from  the  YP  maps.
     if  the  gecos,  dir, or shell entries contain text, it will
override the
     information included via YP.  On some  systems,  the  passwd
field may also
     be  overridden.   It is recommended that the standard way to
enable YP
     passwd support in /etc/master.passwd is:


     which after pwd_mkdb(8) will result in /etc/passwd  containing:


SEE ALSO    [Toc]    [Back]

     chpass(1),  login(1), passwd(1), getpwent(3), login.conf(5),
     adduser(8), pwd_mkdb(8), vipw(8), yp(8)

     Managing NFS and NIS (O'Reilly & Associates)

STANDARDS    [Toc]    [Back]

     The password file format has changed since 4.3BSD.  The following awk(1)
     script  can  be used to convert your old-style password file
into a new
     style  password  file.   The  additional  fields  ``class'',
``change'', and
     ``expire'' are added, but are turned off by default.  To set
change and
     expire use the current day in seconds from  the  epoch  plus
the number of
     seconds of offset desired.

           BEGIN { FS = ":"}
           { print $1 ":" $2 ":" $3 ":" $4 "::0:0:" $5 ":" $6 ":"
$7 }

HISTORY    [Toc]    [Back]

     A passwd file format appeared in Version 3 AT&T UNIX.

     The YP file format first appeared in SunOS.

BUGS    [Toc]    [Back]

     User information should  (and  eventually  will)  be  stored

     Placing  YP exclusions in the file after any inclusions will
have unexpected

OpenBSD     3.6                           July      18,      1995
[ Back ]
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