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.\"	@(#)chpass.1	5.6 (Berkeley) 3/12/89
.\"
.TH CHPASS 1 "March 12, 1989"
.UC 4
.SH NAME
chpass \- add or change user database information
.SH SYNOPSIS
chpass [ -a list ] [ user ]
.SH DESCRIPTION
.I Chpass
allows editing of the user database information associated
with
.I user
or, by default, the current user.
The information is formatted and supplied to an editor for changes.
The
.I vi
editor will be used unless the environmental variable EDITOR selects
an alternate editor.
When the editor terminates, the information is re-read and used to
update the user database itself.
Only the user, or the super-user, may edit the information associated
with the user.
.PP
Only the information that the user is allowed to change is displayed.
.PP
Possible display items are as follows:
.PP
.RS
 Login:			user's login name
 Password:		user's encrypted password
 Uid:			user's id
 Gid:			user's login group id
 Change:			password change time
 Expire:			account expiration time
 Class:			user's general classification
 Home Directory:	user's home directory
 Shell:			user's login shell
 Full Name:		user's real name
 Location:		user's normal location
 Home Phone:		user's home phone
 Office Phone:		user's office phone
.RE
.PP
.PP
The
.I login
field is the user name used to access the computer account.
.PP
The
.I password
field contains the encrypted form of the user's password.
.PP
The
.I uid
field is the number associated with the
.I login
field.
Both of these fields should be unique across the system (and often
across a group of systems) as 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
.I group
field is the group that the user will be placed in upon login.
Since this system supports multiple groups (see
.IR groups (1))
this field currently has little special meaning.
This field may be filled in with either a number or a group name (see
.IR group (5)).
.PP
The
.I change
field is the date by which the password must be changed.
.PP
The
.I expire
field is the date on which the account expires.
.PP
Both the
.I change
and
.I expire
fields should be entered in the form ``month day year'' where
.I month
is the month name (the first three characters are sufficient),
.I day
is the day of the month, and
.I year
is the year.
.PP
The
.I class
field is currently unused.  In the near future it will be a key to
a
.IR termcap (5)
style database of user attributes.
.PP
The user's home directory is the full UNIX path name where the user
will be placed on login.
.PP
The shell field is the command interpreter the user prefers.
If the
.I shell
field is empty, the Bourne shell (\fI/bin/sh\fP) is assumed.
.PP
When altering a login shell, and not the super-user, the user must
select an approved shell from the list in
.IR /etc/shells .
.PP
The last four fields are for storing the user's full name, office
location, and home and work telephone numbers.
.PP
The super-user is also allowed to directly supply a user database
entry, in the format specified by
.IR passwd (5),
as an argument to the
.I -a
option.
This argument must be a colon (``:'') separated list of all the
user database fields, although they may be empty.
.PP
Once the information has been verified,
.I chpass
uses
.IR mkpasswd (8)
to update the user database.  This is run in the background, and,
at very large sites could take several minutes.  Until this update
is completed, the password file is unavailable for other updates
and the new information will not be available to programs.
.SH FILES
.DT
/etc/master.passwd		The user database
/etc/shells			The list of approved shells
.RE
.SH "SEE ALSO"
login(1), finger(1), getusershell(3), passwd(5), mkpasswd(8), vipw(8)
.br
Robert Morris and Ken Thompson,
.I UNIX password security
.SH BUGS
User information should (and eventually will) be stored elsewhere.