CHPASS(1) FreeBSD General Commands Manual CHPASS(1)
NAME
chpass, chfn, chsh, ypchpass, ypchfn, ypchsh - add or change user
database information
SYNOPSIS
chpass [-a list] [-e expiretime] [-p encpass] [-s newshell] [user]
ypchpass [-loy] [-a list] [-d domain] [-e expiretime] [-h host]
[-p encpass] [-s newshell] [user]
DESCRIPTION
The chpass utility allows editing of the user database information
associated with user or, by default, the current user.
The chfn, chsh, ypchpass, ypchfn and ypchsh utilities behave identically
to chpass. (There is only one program.)
The information is formatted and supplied to an editor for changes.
Only the information that the user is allowed to change is displayed.
The options are as follows:
-a list The super-user is allowed to directly supply a user
database entry, in the format specified by passwd(5), as
an argument. This argument must be a colon (":")
separated list of all the user database fields, although
they may be empty.
-e expiretime Change the account expire time. This option is used to
set the expire time from a script as if it was done in the
interactive editor.
-p encpass The super-user is allowed to directly supply an encrypted
password field, in the format used by crypt(3), as an
argument.
-s newshell Attempt to change the user's shell to newshell.
Possible display items are as follows:
Login: user's login name
Password: user's encrypted password
Uid: user's login
Gid: user's login group
Class: user's general classification
Change: password change time
Expire: account expiration time
Full Name: user's real name
Office Location: user's office location (1)
Office Phone: user's office phone (1)
Home Phone: user's home phone (1)
Other Information: any locally defined parameters for user (1)
Home Directory: user's home directory
Shell: user's login shell
NOTE(1) - In the actual master.passwd file, these fields
are comma-delimited fields embedded in the
FullName field.
The login field is the user name used to access the computer account.
The password field contains the encrypted form of the user's password.
The uid field is the number associated with the login field. Both of
these fields should be unique across the system (and often across a group
of systems) as they control file access.
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.
The gid field is the group that the user will be placed in at login.
Since BSD supports multiple groups (see groups(1)) this field currently
has little special meaning. This field may be filled in with either a
number or a group name (see group(5)).
The class field references class descriptions in /etc/login.conf and is
typically used to initialize the user's system resource limits when they
login.
The change field is the date by which the password must be changed.
The expire field is the date on which the account expires.
Both the change and expire fields should be entered in the form "month
day year" where month is the month name (the first three characters are
sufficient), day is the day of the month, and year is the year.
Five fields are available for storing the user's full name, office
location, work and home telephone numbers and finally other information
which is a single comma delimited string to represent any additional
gecos fields (typically used for site specific user information). Note
that finger(1) will display the office location and office phone together
under the heading Office:.
The user's home directory is the full UNIX path name where the user will
be placed at login.
The shell field is the command interpreter the user prefers. If the
shell field is empty, the Bourne shell, /bin/sh, is assumed. When
altering a login shell, and not the super-user, the user may not change
from a non-standard shell or to a non-standard shell. Non-standard is
defined as a shell not found in /etc/shells.
Once the information has been verified, chpass uses pwd_mkdb(8) to update
the user database.
ENVIRONMENT
The vi(1) editor will be used unless the environment variable EDITOR is
set to 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.
See pwd_mkdb(8) for an explanation of the impact of setting the
PW_SCAN_BIG_IDS environment variable.
NIS INTERACTION
The chpass utility can also be used in conjunction with NIS, however some
restrictions apply. Currently, chpass can only make changes to the NIS
passwd maps through rpc.yppasswdd(8), which normally only permits changes
to a user's password, shell and GECOS fields. Except when invoked by the
super-user on the NIS master server, chpass (and, similarly, passwd(1))
cannot use the rpc.yppasswdd(8) server to change other user information
or add new records to the NIS passwd maps. Furthermore, rpc.yppasswdd(8)
requires password authentication before it will make any changes. The
only user allowed to submit changes without supplying a password is the
super-user on the NIS master server; all other users, including those
with root privileges on NIS clients (and NIS slave servers) must enter a
password. (The super-user on the NIS master is allowed to bypass these
restrictions largely for convenience: a user with root access to the NIS
master server already has the privileges required to make updates to the
NIS maps, but editing the map source files by hand can be cumbersome.
Note: these exceptions only apply when the NIS master server is a FreeBSD
system).
Consequently, except where noted, the following restrictions apply when
chpass is used with NIS:
1. Only the shell and GECOS information may be changed. All
other fields are restricted, even when chpass is invoked by
the super-user. While support for changing other fields could
be added, this would lead to compatibility problems with other
NIS-capable systems. Even though the super-user may supply
data for other fields while editing an entry, the extra
information (other than the password -- see below) will be
silently discarded.
Exception: the super-user on the NIS master server is
permitted to change any field.
2. Password authentication is required. The chpass utility will
prompt for the user's NIS password before effecting any
changes. If the password is invalid, all changes will be
discarded.
Exception: the super-user on the NIS master server is allowed
to submit changes without supplying a password. (The super-
user may choose to turn off this feature using the -o flag,
described below.)
3. Adding new records to the local password database is
discouraged. The chpass utility will allow the administrator
to add new records to the local password database while NIS is
enabled, but this can lead to some confusion since the new
records are appended to the end of the master password file,
usually after the special NIS '+' entries. The administrator
should use vipw(8) to modify the local password file when NIS
is running.
The super-user on the NIS master server is permitted to add
new records to the NIS password maps, provided the
rpc.yppasswdd(8) server has been started with the -a flag to
permitted additions (it refuses them by default). The chpass
utility tries to update the local password database by
default; to update the NIS maps instead, invoke chpass with
the -y flag.
4. Password changes are not permitted. Users should use
passwd(1) or yppasswd(1) to change their NIS passwords. The
super-user is allowed to specify a new password (even though
the "Password:" field does not show up in the editor template,
the super-user may add it back by hand), but even the super-
user must supply the user's original password otherwise
rpc.yppasswdd(8) will refuse to update the NIS maps.
Exception: the super-user on the NIS master server is
permitted to change a user's NIS password with chpass.
There are also a few extra option flags that are available when chpass is
compiled with NIS support:
-d domain Specify a particular NIS domain. The chpass utility uses the
system domain name by default, as set by the domainname(1)
utility. The -d option can be used to override a default, or
to specify a domain when the system domain name is not set.
-h host Specify the name or address of an NIS server to query.
Normally, chpass will communicate with the NIS master host
specified in the master.passwd or passwd maps. On hosts that
have not been configured as NIS clients, there is no way for
the program to determine this information unless the user
provides the hostname of a server. Note that the specified
hostname need not be that of the NIS master server; the name
of any server, master or slave, in a given NIS domain will do.
When using the -d option, the hostname defaults to
"localhost". The -h option can be used in conjunction with
the -d option, in which case the user-specified hostname will
override the default.
-l Force chpass to modify the local copy of a user's password
information in the event that a user exists in both the local
and NIS databases.
-o Force the use of RPC-based updates when communicating with
rpc.yppasswdd(8) ("old-mode"). When invoked by the super-user
on the NIS master server, chpass allows unrestricted changes
to the NIS passwd maps using dedicated, non-RPC-based
mechanism (in this case, a UNIX domain socket). The -o flag
can be used to force chpass to use the standard update
mechanism instead. This option is provided mainly for testing
purposes.
-y Opposite effect of -l. This flag is largely redundant since
chpass operates on NIS entries by default if NIS is enabled.
FILES
/etc/master.passwd the user database
/etc/passwd a Version 7 format password file
/etc/chpass.XXXXXX temporary copy of the password file
/etc/shells the list of approved shells
EXAMPLES
Change the shell of the current user to `/usr/local/bin/zsh':
chsh -s /usr/local/bin/zsh
SEE ALSO
finger(1), login(1), passwd(1), getusershell(3), login.conf(5),
passwd(5), pw(8), pwd_mkdb(8), vipw(8)
Robert Morris and Ken Thompson, UNIX Password security.
HISTORY
The chpass utility appeared in 4.3BSD-Reno.
BUGS
User information should (and eventually will) be stored elsewhere.
FreeBSD 13.1-RELEASE-p6 November 17, 2020 FreeBSD 13.1-RELEASE-p6
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