PW(8)

NAME

pw - create, remove, modify & display system users and

groups

SYNOPSIS

pw [-V etcdir] useradd [name|uid] [-C config] [-q] [-n name]
[-u uid]
   [-c comment] [-d dir] [-e date] [-p date] [-g group]  [-G
grouplist]
   [-m]  [-k dir] [-w method] [-s shell] [-o] [-L class] [-h
fd | -H fd]
   [-N] [-P] [-Y]
pw [-V etcdir] useradd [name|uid] -D [-C  config]  [-q]  [-b
dir] [-e days]
   [-p days] [-g group] [-G grouplist] [-k dir] [-u min,max]
[-i min,max]
   [-w method] [-s shell] [-y path]
pw [-V etcdir] userdel [name|uid] [-n name]  [-u  uid]  [-r]
[-Y]
pw [-V etcdir] usermod [name|uid] [-C config] [-q] [-n name]
[-u uid]
   [-c comment] [-d dir] [-e date] [-p date] [-g group]  [-G
grouplist]
   [-l name] [-m] [-k dir] [-w method] [-s shell] [-L class]
   [-h fd | -H fd] [-N] [-P] [-Y]
pw [-V etcdir] usershow [name|uid] [-n name] [-u  uid]  [-F]
[-P] [-7] [-a]
pw [-V etcdir] usernext [-C config] [-q]
pw  [-V  etcdir]  groupadd  [group|gid] [-C config] [-q] [-n
group] [-g gid]
   [-M members] [-o] [-h fd | -H fd] [-N] [-P] [-Y]
pw [-V etcdir] groupdel [group|gid] [-n name] [-g gid] [-Y]
pw [-V etcdir] groupmod [group|gid]  [-C  config]  [-q]  [-n
name] [-g gid]
   [-l  name]  [-M  members] [-m newmembers] [-h fd | -H fd]
[-N] [-P] [-Y]
pw [-V etcdir] groupshow [group|gid] [-n name] [-g gid] [-F]
[-P] [-a]
pw [-V etcdir] groupnext [-C config] [-q]
pw [-V etcdir] lock [name|uid] [-C config] [-q]
pw [-V etcdir] unlock [name|uid] [-C config] [-q]

DESCRIPTION

The pw utility is a command-line based editor for the system

user and
group files, allowing the superuser an easy to use and stan

dardized way
of adding, modifying and removing users and groups. Note

that pw only
operates on the local user and group files. NIS users and

groups must be
maintained on the NIS server. The pw utility handles updat

ing the
passwd, master.passwd, group and the secure and insecure

password
database files, and must be run as root.

The first one or two keywords provided to pw on the command

line provide
the context for the remainder of the arguments. The key

words user and
group may be combined with add, del, mod, show, or next in

any order.
(For example, showuser, usershow, show user, and user show

all mean the
same thing.) This flexibility is useful for interactive

scripts calling
pw for user and group database manipulation. Following

these keywords,
you may optionally specify the user or group name or numeric

id as an
alternative to using the -n name, -u uid, -g gid options.

The following flags are common to most or all modes of oper

ation:

-V etcdir This flag sets an alternate location for the

password,

group and configuration files, and may be used

to maintain
a user/group database in an alternate loca

tion. If this
switch is specified, the system /etc/pw.conf

will not be
sourced for default configuration data, but

the file
pw.conf in the specified directory will be

used instead (or
none, if it does not exist). The -C flag may

be used to
override this behaviour. As an exception to

the general
rule where options must follow the operation

type, the -V
flag may be used on the command line before

the operation
keyword.

-C config By default, pw reads the file /etc/pw.conf to

obtain policy

information on how new user accounts and

groups are to be
created. The -C option specifies a different

configuration
file. While most of the contents of the con

figuration file
may be overridden via command-line options, it

may be more
convenient to keep standard information in a

configuration
file.

-q Use of this option causes pw to suppress error

messages,

which may be useful in interactive environ

ments where it is
preferable to interpret status codes returned

by pw rather
than messing up a carefully formatted display.

-N This option is available in add and modify op

erations, and

tells pw to output the result of the operation

without
updating the user or group databases. You may

use the -P
option to switch between standard passwd and

readable formats.

-Y Using this option with any of the update modes

causes pw to

run make(1) after changing to the directory

/var/yp. This
is intended to allow automatic updating of NIS

database
files. If separate passwd and group files are

being used
by NIS, then use the -y path option to specify

the location
of the NIS passwd database so that pw will

concurrently
update it with the system password databases.

USER OPTIONS

The following options apply to the useradd and usermod com

mands:

-n name Specify the user/account name.

-u uid Specify the user/account numeric id.

Usually, you only need to provide one or the

other of these
options, as the account name will imply the

uid, or vice
versa. However, there are times when you need

to provide
both. For example, when changing the uid of

an existing
user with usermod, or overriding the default

uid when creating a new account. If you wish pw to auto

matically allocate the uid to a new user with useradd, then

you should
not use the -u option. You may also provide

either the
account or userid immediately after the

useradd, userdel,
usermod or usershow keywords on the command

line without
using the -n or -u options.

-c comment This field sets the contents of the passwd

GECOS field,

which normally contains up to four comma-sepa

rated fields
containing the user's full name, office or lo

cation, and
work and home phone numbers. These sub-fields

are used by
convention only, however, and are optional.

If this field
is to contain spaces, you need to quote the

comment itself
with double quotes `"'. Avoid using commas in

this field
as these are used as sub-field separators, and

the colon
`:' character also cannot be used as this is

the field separator for the passwd file itself.

-d dir This option sets the account's home directory.

Normally,

you will only use this if the home directory

is to be different from the default determined from

/etc/pw.conf - normally /home with the account name as a subdi

rectory.

-e date Set the account's expiration date. Format of

the date is

either a UNIX time in decimal, or a date in

`dd-mmm-yy[yy]'
format, where dd is the day, mmm is the month,

either in
numeric or alphabetic format ('Jan', 'Feb',

etc) and year
is either a two or four digit year. This op

tion also
accepts a relative date in the form `+n[mhd

woy]' where `n'
is a decimal, octal (leading 0) or hexadecimal

(leading 0x)
digit followed by the number of Minutes,

Hours, Days,
Weeks, Months or Years from the current date

at which the
expiration date is to be set.

-p date Set the account's password expiration date.

This field is

similar to the account expiration date option,

except that
it applies to forced password changes. This

is set in the
same manner as the -e option.

-g group Set the account's primary group to the given

group. group

may be defined by either its name or group

number.

-G grouplist Set additional group memberships for an ac

count. grouplist

is a comma-separated list of group names or

group numbers.
The user's name is added to the group lists in

/etc/group,
and removed from any groups not specified in

grouplist.
Note: a user should not be added to their pri

mary group
with grouplist. Also, group membership

changes do not take
effect for current user login sessions, re

quiring the user
to reconnect to be affected by the changes.

-L class This option sets the login class for the user

being cre

ated. See login.conf(5) and passwd(5) for

more information
on user login classes.

-m This option instructs pw to attempt to create

the user's

home directory. While primarily useful when

adding a new
account with useradd, this may also be of use

when moving
an existing user's home directory elsewhere on

the file
system. The new home directory is populated

with the contents of the skeleton directory, which typi

cally contains a
set of shell configuration files that the user

may personalize to taste. When -m is used on an account

with
usermod, existing configuration files in the

user's home
directory are not overwritten from the skele

ton files.

When a user's home directory is created, it

will by default
be a subdirectory of the basehome directory as

specified by
the -b option (see below), bearing the name of

the new
account. This can be overridden by the -d op

tion on the
command line, if desired.

-k dir Set the skeleton directory, from which basic

startup and

configuration files are copied when the user's

home directory is created. This option only has meaning

when used
with the -d or -m flags.

-s shell Set or changes the user's login shell to

shell. If the

path to the shell program is omitted, pw

searches the
shellpath specified in /etc/pw.conf and fills

it in as
appropriate. Note that unless you have a spe

cific reason
to do so, you should avoid specifying the path

- this will
allow pw to validate that the program exists

and is executable. Specifying a full path (or supplying

a blank ""
shell) avoids this check and allows for such

entries as
/nonexistent that should be set for accounts

not intended
for interactive login.

-h fd This option provides a special interface by

which interac

tive scripts can set an account password using

pw. Because
the command line and environment are fundamen

tally insecure
mechanisms by which programs can accept infor

mation, pw
will only allow setting of account and group

passwords via
a file descriptor (usually a pipe between an

interactive
script and the program). sh, bash, ksh and

perl all possess mechanisms by which this can be done.

Alternatively,
pw will prompt for the user's password if -h 0

is given,
nominating stdin as the file descriptor on

which to read
the password. Note that this password will be

read only
once and is intended for use by a script

rather than for
interactive use. If you wish to have new

password confirmation along the lines of passwd(1), this must

be implemented as part of an interactive script that

calls pw.

If a value of `-' is given as the argument fd,

then the
password will be set to `*', rendering the ac

count inaccessible via password-based login.

-H fd Read an encrypted password string from the

specified file

descriptor. This is like -h, but the password

should be
supplied already encrypted in a form suitable

for writing
directly to the password database.

It is possible to use useradd to create a new account that

duplicates an
existing user id. While this is normally considered an er

ror and will be
rejected, the -o option overrides the check for duplicates

and allows the
duplication of the user id. This may be useful if you allow

the same
user to login under different contexts (different group al

locations, different home directory, different shell) while providing ba

sically the
same permissions for access to the user's files in each ac

count.

The useradd command also has the ability to set new user and

group
defaults by using the -D option. Instead of adding a new

user, pw writes
a new set of defaults to its configuration file,

/etc/pw.conf. When
using the -D option, you must not use either -n name or -u

uid or an
error will result. Use of -D changes the meaning of several

command line
switches in the useradd command. These are:

-D Set default values in /etc/pw.conf configura

tion file, or a

different named configuration file if the -C

config option
is used.

-b dir Set the root directory in which user home di

rectories are

created. The default value for this is /home,

but it may
be set elsewhere as desired.

-e days Set the default account expiration period in

days. Unlike

use without -D, the argument must be numeric,

which specifies the number of days after creation when

the account is
to expire. A value of 0 suppresses automatic

calculation
of the expiry date.

-p days Set the default password expiration period in

days.

-g group Set the default group for new users. If a

blank group is

specified using -g "", then new users will be

allocated
their own private primary group with the same

name as their
login name. If a group is supplied, either

its name or uid
may be given as an argument.

-G grouplist Set the default groups in which new users are

granted mem

bership. This is a separate set of groups

from the primary
group, and you should avoid nominating the

same group as
both primary and extra groups. In other

words, these extra
groups determine membership in groups other

than the primary group. grouplist is a comma-separated

list of group
names or ids, and are always stored in

/etc/pw.conf by
their symbolic names.

-L class This option sets the default login class for

new users.

-k dir Set the default skeleton directory, from which

prototype

shell and other initialization files are

copied when pw
creates a user's home directory.

-u min,max, -i min,max

These options set the minimum and maximum user

and group
ids allocated for new accounts and groups cre

ated by pw.
The default values for each is 1000 minimum

and 32000 maximum. min and max are both numbers, where max

must be
greater than min, and both must be between 0

and 32767. In
general, user and group ids less than 100 are

reserved for
use by the system, and numbers greater than

32000 may also
be reserved for special purposes (used by some

system daemons).

-w method The -w option sets the default method used to

set passwords

for newly created user accounts. method is

one of:

no disable login on newly created

accounts
yes force the password to be the ac

count name
none force a blank password
random generate a random password

The `random' or `no' methods are the most se

cure; in the
former case, pw generates a password and

prints it to stdout, which is suitable where you issue users

with passwords
to access their accounts rather than having

the user nominate their own (possibly poorly chosen) pass

word. The `no'
method requires that the superuser use pass

wd(1) to render
the account accessible with a password.

-y path This sets the pathname of the database used by

NIS if you

are not sharing the information from

/etc/master.passwd
directly with NIS. You should only set this

option for NIS
servers.

The userdel command has only three valid options. The -n

name and -u uid
options have already been covered above. The additional op

tion is:

-r This tells pw to remove the user's home direc

tory and all

of its contents. The pw utility errs on the

side of caution when removing files from the system.

Firstly, it will
not do so if the uid of the account being re

moved is also
used by another account on the system, and the
directory in the password file is a valid path

that commences with the character `/'. Secondly, it

will only
remove files and directories that are actually

owned by the
user, or symbolic links owned by anyone under

the user's
home directory. Finally, after deleting all

contents owned
by the user only empty directories will be re

moved. If any
additional cleanup work is required, this is

left to the
administrator.

Mail spool files and crontabs are always removed when an ac

count is
deleted as these are unconditionally attached to the user

name. Jobs
queued for processing by at are also removed if the user's

uid is unique
and not also used by another account on the system.

The usershow command allows viewing of an account in one of

two formats.
By default, the format is identical to the format used in
/etc/master.passwd with the password field replaced with a

`*'. If the
-P option is used, then pw outputs the account details in a

more human
readable form. If the -7 option is used, the account de

tails are shown
in v7 format. The -a option lists all users currently on

file. Using -F
forces pw to print the details of an account even if it does

not exist.

The command usernext returns the next available user and

group ids separated by a colon. This is normally of interest only to in

teractive
scripts or front-ends that use pw.

GROUP OPTIONS

The -C and -q options (explained at the start of the previ

ous section)
are available with the group manipulation commands. Other

common options
to all group-related commands are:

-n name Specify the group name.

-g gid Specify the group numeric id.

As with the account name and id fields, you

will usually
only need to supply one of these, as the

group name
implies the uid and vice versa. You will on

ly need to use
both when setting a specific group id against

a new group
or when changing the uid of an existing

group.

-M memberlist This option provides an alternative way to

add existing

users to a new group (in groupadd) or replace

an existing
membership list (in groupmod). memberlist is

a comma separated list of valid and existing user names

or uids.

-m newmembers Similar to -M, this option allows the

addition of existing

users to a group without replacing the exist

ing list of
members. Login names or user ids may be

used, and duplicate users are silently eliminated.

groupadd also has a -o option that allows allocation of an

existing group
id to a new group. The default action is to reject an at

tempt to add a
group, and this option overrides the check for duplicate

group ids.
There is rarely any need to duplicate a group id.

The groupmod command adds one additional option:

-l name This option allows changing of an existing

group name to

`name'. The new name must not already exist,

and any
attempt to duplicate an existing group name

will be
rejected.

Options for groupshow are the same as for usershow, with the

-g gid
replacing -u uid to specify the group id. The -7 option

does not apply
to the groupshow command.

The command groupnext returns the next available group id on

standard
output.

USER LOCKING

The pw utility supports a simple password locking mechanism

for users; it
works by prepending the string `*LOCKED*' to the beginning

of the password field in master.passwd to prevent successful authenti

cation.

The lock and unlock commands take a user name or uid of the

account to
lock or unlock, respectively. The -V, -C, and -q options as

described
above are accepted by these commands.

NOTES

For a summary of options available with each command, you

can use

pw [command] help

For example,

pw useradd help

lists all available options for the useradd operation.

The pw utility allows 8-bit characters in the passwd GECOS

field (user's
full name, office, work and home phone number subfields),

but disallows
them in user login and group names. Use 8-bit characters

with caution,
as connection to the Internet will require that your mail

transport program supports 8BITMIME, and will convert headers containing

8-bit characters to 7-bit quoted-printable format. sendmail(8) does

support this.
Use of 8-bit characters in the GECOS field should be used in

conjunction
with the user's default locale and character set and should

not be implemented without their use. Using 8-bit characters may also

affect other
programs that transmit the contents of the GECOS field over

the Internet,
such as fingerd(8), and a small number of TCP/IP clients,

such as IRC,
where full names specified in the passwd file may be used by

default.

The pw utility writes a log to the /var/log/userlog file

when actions
such as user or group additions or deletions occur. The lo

cation of this
logfile can be changed in pw.conf(5).

FILES

/etc/master.passwd The user database
/etc/passwd A Version 7 format password file
/etc/login.conf The user capabilities database
/etc/group The group database
/etc/master.passwd.new Temporary copy of the master pass

word file
/etc/passwd.new Temporary copy of the Version 7

password file
/etc/group.new Temporary copy of the group file
/etc/pw.conf Pw default options file
/var/log/userlog User/group modification logfile

EXIT STATUS

The pw utility returns EXIT_SUCCESS on successful operation,

otherwise pw
returns one of the following exit codes defined by sysex

its(3) as follows:

EX_USAGE

+o Command line syntax errors (invalid keyword, un

known option).

EX_NOPERM

+o Attempting to run one of the update modes as non

root.

EX_OSERR

+o Memory allocation error.
+o Read error from password file descriptor.

EX_DATAERR

+o Bad or invalid data provided or missing on the

command line or

via the password file descriptor.

+o Attempted to remove, rename root account or change

its uid.

EX_OSFILE

+o Skeleton directory is invalid or does not exist.
+o Base home directory is invalid or does not exist.
+o Invalid or non-existent shell specified.

EX_NOUSER

+o User, user id, group or group id specified does

not exist.
+o User or group recorded, added, or modified unex

pectedly disap

peared.

EX_SOFTWARE

+o No more group or user ids available within speci

fied range.

EX_IOERR

+o Unable to rewrite configuration file.
+o Error updating group or user database files.
+o Update error for passwd or group database files.

EX_CONFIG

+o No base home directory configured.

SEE ALSO

chpass(1), passwd(1), group(5), login.conf(5), passwd(5),

pw.conf(5),
pwd_mkdb(8), vipw(8)

HISTORY

The pw utility was written to mimic many of the options used

in the SYSV
shadow support suite, but is modified for passwd and group

fields specific to the 4.4BSD operating system, and combines all of

the major elements into a single command.

BSD January 11, 2004

BSD