Tribblix: manual page: usermod.8

USERMOD(8) Maintenance Commands and Procedures USERMOD(8)

NAME

usermod - modify a user's login information on the system

SYNOPSIS

usermod [-u uid [-o]] [-g group] [-G group[,group]...]
[-d dir [-m [-z|-Z]]] [-s shell] [-c comment] [-l new_name]
[-f inactive] [-e expire]
[-A authorization[,authorization]...]
[-P profile[,profile]...] [-R role[,role]...]
[-K key=value] login

DESCRIPTION

The usermod utility modifies a user's login definition on the system.
It changes the definition of the specified login and makes the
appropriate login-related system file and file system changes.

The system file entries created with this command have a limit of 512
characters per line. Specifying long arguments to several options can
exceed this limit.

OPTIONS

The following options are supported:

-A authorization

One or more comma separated authorizations as defined in
auth_attr(5). Only a user or role who has grant rights to the
authorization can assign it to an account. This replaces any
existing authorization setting. If an empty authorization list is
specified, the existing setting is removed.

-c comment

Specify a comment string. comment can be any text string. It is
generally a short description of the login, and is currently used
as the field for the user's full name. This information is stored
in the user's /etc/passwd entry.

-d dir

Specify the new home directory of the user. It defaults to
base_dir/login, where base_dir is the base directory for new
login home directories, and login is the new login.

-e expire

Specify the expiration date for a login. After this date, no user
will be able to access this login. The expire option argument is
a date entered using one of the date formats included in the
template file /etc/datemsk. See getdate(3C).

For example, you may enter 10/6/90 or October 6, 1990. A value of
`` '' defeats the status of the expired date.

-f inactive

Specify the maximum number of days allowed between uses of a
login ID before that login ID is declared invalid. Normal values
are positive integers. A value of 0 defeats the status.

-g group

Specify an existing group's integer ID or character-string name.
It redefines the user's primary group membership.

-G group

One or more comma-separated existing groups, specified by integer
ID or character-string name. It redefines the user's
supplementary group membership. Any duplicate groups between the
-g and -G options are ignored. No more than NGROUPS_UMAX groups
may be specified as defined in <sys/param.h>.

-K key=value

Replace existing or add to a user's key=value pair attributes.
Multiple -K options can be used to replace or add multiple
key=value pairs. However, keys must not be repeated. The generic
-K option with the appropriate key can be used instead of the
specific implied key options (-A, -P, -R, -p). See user_attr(5)
for a list of valid keys. Values for these keys are usually found
in man pages or other sources related to those keys. For example,
see project(5) for guidance on values for the project key. Use
the command ppriv(1) with the -v and -l options for a list of
values for the keys defaultpriv and limitpriv.

The keyword type can be specified with the value role or the
value normal. When using the value role, the account changes
from a normal user to a role; using the value normal keeps the
account a normal user.

As a role account, no roles (-R or roles=value) can be present.

-l new_logname

Specify the new login name for the user. See passwd(5) for the
requirements for usernames.

-m [-z|-Z]

Move the user's home directory to the new directory specified
with the -d option. If the directory already exists, it must have
permissions read/write/execute by group, where group is the
user's primary group.

If the user's old home directory was located on a separate ZFS
file system and the /etc/default/useradd file contains the
parameter MANAGE_ZFS set to the value YES, the file system will
be destroyed after the home directory is moved. If the parent
directory of the user's new home directory is located on a
separate ZFS filesystem and the /etc/default/useradd file
contains the parameter MANAGE_ZFS set to the value YES, a new ZFS
file system will be created.

If the -z option is specified, usermod will always try to create
a new file system for the home directory and destroy the old one.

If the -Z option is specified, a new file system will never be
created, and the old one will never be destroyed.

-o

This option allows the specified UID to be duplicated (non-
unique).

-P profile

One or more comma-separated execution profiles defined in
prof_attr(5). This replaces any existing profile setting in
user_attr(5). If an empty profile list is specified, the existing
setting is removed.

-R role

One or more comma-separated roles (see roleadd(8)). This replaces
any existing role setting. If an empty role list is specified,
the existing setting is removed.

-s shell

Specify the full pathname of the program that is used as the
user's shell on login. The value of shell must be a valid
executable file.

-u uid

Specify a new UID for the user. It must be a non-negative decimal
integer less than MAXUID as defined in <sys/param.h>. The UID
associated with the user's home directory is not modified with
this option; a user will not have access to their home directory
until the UID is manually reassigned using chown(1).

OPERANDS

The following operands are supported:

login

An existing login name to be modified.

EXAMPLES

Example 1: Assigning Privileges to a User

The following command adds the privilege that affects high resolution
times to a user's initial, inheritable set of privileges.

# usermod -K defaultpriv=basic,proc_clock_highres jdoe

This command results in the following entry in user_attr:

jdoe::::type=normal;defaultpriv=basic,proc_clock_highres

Example 2: Removing a Privilege from a User's Limit Set

The following command removes the privilege that allows the specified
user to create hard links to directories and to unlink directories.

# usermod -K limitpriv=all,!sys_linkdir jdoe

This command results in the following entry in user_attr:

jdoe::::type=normal;defaultpriv=basic,limitpriv=all,!sys_linkdir

Example 3: Removing a Privilege from a User's Basic Set

The following command removes the privilege that allows the specified
user to examine processes outside the user's session.

# usermod -K defaultpriv=basic,!proc_session jdoe

This command results in the following entry in user_attr:

jdoe::::type=normal;defaultpriv=basic,!proc_session;limitpriv=all

Example 4: Assigning a Role to a User

The following command assigns a role to a user. The role must have
been created prior to this command, see roleadd(8).

# usermod -R mailadm jdoe

This command results in the following entry in user_attr:

jdoe::::type=normal;roles=mailadm;defaultpriv=basic;limitpriv=all

Example 5: Removing All Profiles from a User

The following command removes all profiles that were granted to a
user directly. The user will still have any execution profiles that
are granted by means of the PROFS_GRANTED key in policy.conf(5).

# usermod -P "" jdoe

EXIT STATUS

In case of an error, usermod prints an error message and exits with
one of the following values:

2

The command syntax was invalid. A usage message for the usermod
command is displayed.

3

An invalid argument was provided to an option.

4

The uid given with the -u option is already in use.

5

The password files contain an error. pwconv(8) can be used to
correct possible errors. See passwd(5).

6

The login to be modified does not exist, the group does not
exist, or the login shell does not exist.

8

The login to be modified is in use.

9

The new_logname is already in use.

10

Cannot update the /etc/group or /etc/user_attr file. Other update
requests will be implemented.

11

Insufficient space to move the home directory (-m option). Other
update requests will be implemented.

12

Unable to complete the move of the home directory to the new home
directory.

FILES

/etc/default/useradd

configuration file for user and role administrative commands

/etc/group

system file containing group definitions

/etc/datemsk

system file of date formats

/etc/passwd

system password file

/etc/shadow

system file containing users' and roles' encrypted passwords and
related information

/etc/user_attr

system file containing additional user and role attributes

ATTRIBUTES

NOTES

The usermod utility modifies passwd definitions only in the local
/etc/passwd and /etc/shadow files. If a network nameservice is being
used to supplement the local files with additional entries, usermod
cannot change information supplied by the network nameservice.
However usermod will verify the uniqueness of user name and user ID
against the external nameservice.

The usermod utility uses the /etc/datemsk file for date formatting.

January 7, 2018 USERMOD(8)