.\" $NetBSD: passwd.5,v 1.33.8.1 2019/09/05 08:19:41 martin Exp $ .\" .\" Copyright (c) 1988, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. 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IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, .\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES .\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR .\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER .\" CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)passwd.5 8.1 (Berkeley) 6/5/93 .\" .Dd September 1, 2019 .Dt PASSWD 5 .Os .Sh NAME .Nm passwd , .Nm master.passwd .Nd format of the password file .Sh DESCRIPTION The .Nm passwd files are the local source of password information. They can be used in conjunction with the Hesiod domain .Sq passwd and the .Tn NIS maps .Sq passwd.byname , .Sq passwd.byuid , .Sq master.passwd.byname , and .Sq master.passwd.byuid , as controlled by .Xr nsswitch.conf 5 . .Pp The .Nm master.passwd file is readable only by root, and consists of newline separated .Tn ASCII records, one per user, containing ten colon .Pq Dq \&: separated fields. .Pp Each line has the form: .Dl name:password:uid:gid:class:change:expire:gecos:home_dir:shell .Pp These fields are as follows: .Bl -tag -width password -offset indent -compact .It Em name User's login name. .It Em password User's .Em encrypted password. .It Em uid User's id. .It Em gid User's login group id. .It Em class User's login class. .It Em change Password change time. .It Em expire Account expiration time. .It Em gecos General information about the user. .It Em home_dir User's home directory. .It Em shell User's login shell. .El .Pp Be aware that each line is limited to 1024 characters; longer ones will be ignored. This limit can be queried through .Xr sysconf 3 by using the .Li _SC_GETPW_R_SIZE_MAX parameter. .Pp The .Nm file is generated from the .Nm master.passwd file by .Xr pwd_mkdb 8 , has the .Em class , .Em change , and .Em expire fields removed, and the .Em password field replaced by a .Dq \&* . .Pp The .Em name field is the login used to access the computer account, and the .Em 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. .Pp While it is possible to have multiple entries with identical login names and/or identical user id's, it is usually a mistake to do so. Routines that manipulate these files will often return only one of the multiple entries, and that one by random selection. .Pp The login name must never begin with a hyphen .Pq Dq \&- ; also, it is strongly suggested that neither upper-case characters nor dots .Pq Dq \&. be part of the name, as this tends to confuse mailers. No field may contain a colon .Pq Dq \&: as this has been used historically to separate the fields in the user database. .Pp The .Em password field is the .Em encrypted form of the password. If the .Em password field is empty, no password will be required to gain access to the machine. This is almost invariably a mistake. Because these files contain the encrypted user passwords, they should not be readable by anyone without appropriate privileges. For the possible ciphers used in this field see .Xr passwd.conf 5 . .Pp The .Em gid field is the group that the user will be placed in upon login. Since this system supports multiple groups (see .Xr groups 1 ) this field currently has little special meaning. .Pp The .Em class field is a key for a user's login class. Login classes are defined in .Xr login.conf 5 , which is a .Xr capfile 5 style database of user attributes, accounting, resource and environment settings. .Pp The .Em change field is the number of seconds from the epoch, .Dv UTC , until the password for the account must be changed. This field may be left empty to turn off the password aging feature. If this is set to .Dq -1 then the user will be prompted to change their password at the next login. .Pp The .Em expire field is the number of seconds from the epoch, .Dv UTC , until the account expires. This field may be left empty to turn off the account aging feature. .Pp If either of the .Em change or .Em expire fields are set, the system will remind the user of the impending change or expiry if they login within a configurable period (defaulting to 14 days) before the event. .Pp The .Em gecos field normally contains comma .Pq Dq \&, separated subfields as follows: .Pp .Bl -tag -width office -offset indent -compact .It Em name user's full name .It Em office user's office number .It Em wphone user's work phone number .It Em hphone user's home phone number .El .Pp The full name may contain an ampersand .Pq Dq \&& which will be replaced by the capitalized login name when the gecos field is displayed or used by various programs such as .Xr finger 1 , .Xr sendmail 1 , etc. .Pp The office and phone number subfields are used by the .Xr finger 1 program, and possibly other applications. .Pp The user's home directory is the full .Ux path name where the user will be placed on login. .Pp The shell field is the command interpreter the user prefers. If there is nothing in the .Em shell field, the Bourne shell .Pq Pa /bin/sh is assumed. .Sh HESIOD SUPPORT If .Sq dns is specified for the .Sq passwd database in .Xr nsswitch.conf 5 , then .Nm lookups occur from the .Sq passwd Hesiod domain. .Sh NIS SUPPORT If .Sq nis is specified for the .Sq passwd database in .Xr nsswitch.conf 5 , then .Nm lookups occur from the .Sq passwd.byname , .Sq passwd.byuid , .Sq master.passwd.byname , and .Sq master.passwd.byuid .Tn NIS maps. .Sh COMPAT SUPPORT If .Sq compat is specified for the .Sq passwd database, and either .Sq dns or .Sq nis is specified for the .Sq passwd_compat database in .Xr nsswitch.conf 5 , then the .Nm file also supports standard .Sq +/- exclusions and inclusions, based on user names and netgroups. .Pp Lines beginning with a minus sign .Pq Dq \&- are entries marked as being excluded from any following inclusions, which are marked with a plus sign .Pq Dq \&+ . .Pp If the second character of the line is an at sign .Pq Dq \&@ , the operation involves the user fields of all entries in the netgroup specified by the remaining characters of the .Em name field. Otherwise, the remainder of the .Em name field is assumed to be a specific user name. .Pp The .Dq \&+ token may also be alone in the .Em name field, which causes all users from either the Hesiod domain .Nm (with .Sq passwd_compat: dns ) or .Sq passwd.byname and .Sq passwd.byuid .Tn NIS maps (with .Sq passwd_compat: nis ) to be included. .Pp If the entry contains non-empty .Em uid or .Em gid fields, the specified numbers will override the information retrieved from the Hesiod domain or the .Tn NIS maps. As well, if the .Em gecos , .Em home_dir or .Em shell entries contain text, it will override the information included via Hesiod or .Tn NIS . On some systems, the .Em passwd field may also be overridden. .Sh COMPATIBILITY The password file format has changed since .Bx 4.3 . The following awk script can be used to convert your old-style password file into a new style password file. The additional fields .Dq class , .Dq change and .Dq expire are added, but are turned off by default. To set them, use the current day in seconds from the epoch + whatever number of seconds of offset you want. .Bd -literal -offset indent BEGIN { FS = ":"} { print $1 ":" $2 ":" $3 ":" $4 "::0:0:" $5 ":" $6 ":" $7 } .Ed .Sh SEE ALSO .Xr chpass 1 , .Xr login 1 , .Xr newgrp 1 , .Xr passwd 1 , .Xr pwhash 1 , .Xr getpwent 3 , .Xr login_getclass 3 , .Xr login.conf 5 , .Xr netgroup 5 , .Xr passwd.conf 5 , .Xr pwd_mkdb 8 , .Xr useradd 8 , .Xr vipw 8 , .Xr yp 8 .Pp .%T "Managing NFS and NIS" (O'Reilly & Associates) .Sh HISTORY A .Nm file format appeared in .At v1 . .Pp The .Tn NIS .Nm file format first appeared in SunOS. .Pp The Hesiod support first appeared in .Nx 1.4 . .Pp The .Xr login.conf 5 capability first appeared in .Nx 1.5 . .Sh BUGS User information should (and eventually will) be stored elsewhere. .Pp Placing .Sq compat exclusions in the file after any inclusions will have unexpected results.