usermod(1M) usermod(1M)
NAME
usermod - modify a user's login information on the system
SYNOPSIS
usermod [-u uid [-U] [-o]] [-g group] [-G group[[,group] . . .]]
[-d dir[-m]] [-s shell] [-c comment] [-l new_logname] [-f inactive]
[-e expire] [-p passgen]
[-a [operator1]event[, . . .]] login
DESCRIPTION
Invoking usermod modifies a user entry in the Identification
and Authentication (I&A) data files. The system file entries
created with this command have a limit of 512 characters per
line. Specifying long arguments to several options may result
in exceeding this limit.
NOTE: This command must be invoked with the -U option to
change the UID on directories and files owned by the user
whose UID is being changed; otherwise, the system
administrator must make such changes.
The following options are available:
-u uid
New user identification number (UID). It must be a
non-negative decimal integer below MAXUID as defined in
sys/param.h. This option is ignored if the login is
administered by the Network Information Service (NIS).
-o This option allows the specified UID to be duplicated
(non-unique). Because the security of the system in
general, and the integrity of the audit trail and
accounting information in particular, depends on every
UID being uniquely associated with a specific
individual, use of this option is discouraged (in order
to maintain user accountability).
-U This option examines a list of pathnames specified in
/etc/default/usermod. Any files or directories in the
specified path list that are owned by the old UID will
have their ownership changed to be that of the new UID.
The path list typically includes the user's home
directory and mail file. This option will also disable a
crontab file under the old UID, and re-enable it under
the new UID. The -u option must also be specified when
this option is used.
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-g group
An existing group's integer ID or character-string name.
It redefines the user's primary group membership. This
option is ignored if the login is administered by the
Network Information Service (NIS).
-G group[[,group] . . .]
One or more comma-separated list elements, each an
existing group's integer ID or character string name.
This list becomes the new supplementary group membership
for the user, replacing any existing supplementary group
list for the user. Duplicates are ignored. The list
specified must be less than NGROUPS_MAX in length, as
the number of supplementary groups for a user, plus the
base group, may never exceed NGROUPS_MAX. This option
is ignored if the login is administered by the Network
Information Service (NIS).
-d dir
The new home directory of the user. This field is
limited to 256 characters.
-m Move the user's home directory to the new directory
specified with the -d option. If the directory already
exists, the specified login must have access to it.
-s shell
Full pathname of the program that is used as the user's
shell on login. This field is limited to 256
characters. The value of shell must be a valid
executable file.
-c comment
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 field is limited to 128
printable characters. This information is stored in the
user's /etc/passwd entry.
-l new_logname
A string of printable characters that specifies the new
login name for the user. It may not contain a colon (:)
or a newline (\n). Also it should not begin with a
capital letter.
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-f inactive
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 turns
off inactive checking.
-e expire
The date on which a login can no longer be used; after
this date, no user will be able to access this login.
(This option is useful for creating temporary logins.)
You may type the value of the argument expire (which is
a date) in any format you like (except a Julian date).
For example, you may enter 10/6/90 or October 6, 1990.
A value of "" turns off expiration checking.
-p passgen
Indicates that the FLAG field in /etc/shadow is to be
set to the specified value. This field is referenced by
the passwd command to determine if a password generator
is in effect for this user. If passgen is neither a
NULL string nor a printable ASCII character, a
diagnostic message is printed.
-a [operator] event(s)
Set the user's audit mask based on the event(s)
specified. An operator can be specified (as + to add or
- to delete) or not specified (to replace). This option
is valid only if the Auditing Utilities are installed.
(To find out which packages are installed on your
system, run the pkginfo command.)
login A string of printable characters that specifies the
existing login name of a user. It must exist and may
not contain a colon (:), or a newline (\n).
If login is preceded by a + or - character, the changes will
be applied to the login administered by the Network
Information Service, not a local user. In this case, the -u,
-g, and -G options, if specified are silently ignored.
Instead, values for the user ID and group ID are taken from
the NIS database.
FILES
/etc/group
/etc/passwd
/etc/security/ia/audit (if the Auditing Utilities are installed)
/etc/security/ia/index
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/etc/security/ia/master
/etc/shadow
REFERENCES
crontab(1), groupadd(1M), groupdel(1M), groupmod(1M),
logins(1M), passwd(1), useradd(1M), userdel(1M), users(1BSD)
DIAGNOSTICS
The usermod command exits with a return code of 0 if
successful. In case of errors, the following messages may be
displayed:
The command syntax was invalid.
An invalid argument was provided to an option.
The uid given with the -u option is already in use.
The login to be modified does not exist or group does
not exist.
The login to be modified is in use.
The new_logname is already in use.
Cannot update the /etc/group file. Other update
requests will be implemented.
Insufficient space to move the home directory (-m
option). Other update requests will be implemented.
Unable to complete the move of the home directory to the
new home directory.
Invalid options -h, -v system service not installed.
Invalid option -a, system service not installed.
Invalid audit event type or class specified.
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