256 lines
7.8 KiB
Groff
256 lines
7.8 KiB
Groff
.\" Copyright (c) 1988, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" From: @(#)passwd.5 8.1 (Berkeley) 6/5/93
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.\" $Id$
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.\"
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.Dd September 29, 1994
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.Dt PASSWD 5
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.Os
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.Sh NAME
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.Nm passwd
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.Nd format of the password file
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.Sh DESCRIPTION
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The
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.Nm passwd
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files are files consisting of newline separated records, one per user,
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containing ten colon (``:'') separated fields. These fields are as
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follows:
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.Pp
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.Bl -tag -width password -offset indent
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.It name
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User's login name.
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.It password
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User's
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.Em encrypted
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password.
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.It uid
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User's id.
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.It gid
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User's login group id.
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.It class
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User's general classification (unused).
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.It change
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Password change time.
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.It expire
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Account expiration time.
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.It gecos
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General information about the user.
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.It home_dir
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User's home directory.
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.It shell
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User's login shell.
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.El
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.Pp
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The
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.Ar name
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field is the login used to access the computer account, and the
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.Ar uid
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field is the number associated with it. They should both be unique
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across the system (and often across a group of systems) since they
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control file access.
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.Pp
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While it is possible to have multiple entries with identical login names
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and/or identical user id's, it is usually a mistake to do so. Routines
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that manipulate these files will often return only one of the multiple
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entries, and that one by random selection.
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.Pp
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The login name must never begin with a hyphen (``-''); also, it is strongly
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suggested that neither upper-case characters or dots (``.'') be part
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of the name, as this tends to confuse mailers. No field may contain a
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colon (``:'') as this has been used historically to separate the fields
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in the user database.
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.Pp
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The password field is the
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.Em encrypted
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form of the password.
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If the
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.Ar password
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field is empty, no password will be required to gain access to the
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machine. This is almost invariably a mistake.
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Because these files contain the encrypted user passwords, they should
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not be readable by anyone without appropriate privileges.
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.Pp
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The group field is the group that the user will be placed in upon login.
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Since this system supports multiple groups (see
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.Xr groups 1 )
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this field currently has little special meaning.
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.Pp
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The
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.Ar class
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field is currently unused. In the near future it will be a key to
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a
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.Xr termcap 5
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style database of user attributes.
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.Pp
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The
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.Ar change
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field is the number in seconds,
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.Dv GMT ,
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from the epoch, until the
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password for the account must be changed.
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This field may be left empty to turn off the password aging feature.
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.Pp
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The
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.Ar expire
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field is the number in seconds,
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.Dv GMT ,
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from the epoch, until the
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account expires.
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This field may be left empty to turn off the account aging feature.
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.Pp
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The
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.Ar gecos
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field normally contains comma (``,'') separated subfields as follows:
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.Pp
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.Bd -unfilled -offset indent
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name user's full name
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office user's office number
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wphone user's work phone number
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hphone user's home phone number
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.Ed
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.Pp
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This information is used by the
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.Xr finger 1
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program.
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.Pp
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The user's home directory is the full
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.Tn UNIX
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path name where the user
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will be placed on login.
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.Pp
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The shell field is the command interpreter the user prefers.
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If there is nothing in the
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.Ar shell
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field, the Bourne shell
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.Pq Pa /bin/sh
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is assumed.
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.Sh YP/NIS INTERACTION
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The
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.Pa /etc/passwd
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file can be configured to enable the YP/NIS group database.
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An entry whose
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.Ar name
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field consists of a plus sign (`+') followed by a login name, will be
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replaced internally to the C library with the YP/NIS password entry for the
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named group. An entry whose
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.Ar name
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field consists of a single plus sign with no login name following,
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will be replaced with the entire YP/NIS
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.Dq Li passwd.byname
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map.
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.Pp
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If any fields other than the login name are left empty, they
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will be used to override the YP/NIS database's values. So, for
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example, an
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.Pa /etc/master.passwd
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entry of:
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.Bd -literal -offset indent
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+:::::::::/etc/noaccess
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.Ed
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would use the entire contents of the YP/NIS password database, but
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each entry would have its designated shell replaced by
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.Pa /etc/noaccess
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(presumably, a program to tell those users that they are not allowed to
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access the machine).
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This is the only way to specify values for the fields which are not
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present in the Sixth Edition format used by YP/NIS.
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.Pp
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If the YP/NIS password database is enabled for any reason, all reverse
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lookups (i.e.,
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.Fn getpwuid )
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will use the entire database, even if only a few logins are enabled.
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Thus, the login name returned by
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.Fn getpwuid
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is not guaranteed to have a valid forward mapping.
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.Sh FILES
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.Bl -tag -width /etc/master.passwd -compact
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.It Pa /etc/passwd
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ASCII password file, with passwords removed
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.It Pa /etc/pwd.db
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.Xr db 3 -format
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password database, with passwords removed
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.It Pa /etc/master.passwd
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ASCII password file, with passwords intact
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.It Pa /etc/spwd.db
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.Xr db 3 -format
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password database, with passwords intact
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.El
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.Sh SEE ALSO
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.Xr adduser 8 ,
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.Xr chpass 1 ,
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.Xr getpwent 3 ,
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.Xr login 1 ,
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.Xr passwd 1 ,
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.Xr pwd_mkdb 8 ,
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.Xr vipw 8 ,
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.Xr yp 4
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.Sh BUGS
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User information should (and eventually will) be stored elsewhere.
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.Pp
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The YP/NIS password database makes encrypted passwords visible to
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ordinary users, thus making password cracking easier.
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.Pp
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The YP/NIS password database is in old-style (Sixth Edition) format,
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and so cannot specify site-wide values for user login class, password
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expiration date, and other fields present in the current format and
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not in the old.
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.Sh COMPATIBILITY
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The password file format has changed since 4.3BSD.
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The following awk script can be used to convert your old-style password
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file into a new style password file.
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The additional fields
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.Dq class ,
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.Dq change
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and
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.Dq expire
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are added, but are turned off by default.
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Class is currently not implemented, but change and expire are; to set them,
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use the current day in seconds from the epoch + whatever number of seconds
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of offset you want.
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.Bd -literal -offset indent
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BEGIN { FS = ":"}
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{ print $1 ":" $2 ":" $3 ":" $4 "::0:0:" $5 ":" $6 ":" $7 }
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.Ed
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.Sh HISTORY
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A
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.Nm
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file format appeared in
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.At v6 .
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The YP/NIS functionality is modeled after
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.Tn SunOS
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and first appeared in
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.Tn FreeBSD
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1.1. The override capability is new in
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.Tn FreeBSD
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2.0.
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