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GROUPADD(8) System Management Commands GROUPADD(8)
NAME
groupadd - create a new group
SYNOPSIS
groupadd [options] group
DESCRIPTION
The groupadd command creates a new group account using the values specified on the command
line plus the default values from the system. The new group will be entered into the
system files as needed.
OPTIONS
The options which apply to the groupadd command are:
-f, --force
This option causes the command to simply exit with success status if the specified
group already exists. When used with -g, and the specified GID already exists, another
(unique) GID is chosen (i.e. -g is turned off).
-g, --gid GID
The numerical value of the group's ID. This value must be unique, unless the -o option
is used. The value must be non-negative. The default is to use the smallest ID value
greater than or equal to GID_MIN and greater than every other group.
See also the -r option and the GID_MAX description.
-h, --help
Display help message and exit.
-K, --key KEY=VALUE
Overrides /etc/login.defs defaults (GID_MIN, GID_MAX and others). Multiple -K options
can be specified.
Example: -K GID_MIN=100 -K GID_MAX=499
Note: -K GID_MIN=10,GID_MAX=499 doesn't work yet.
-o, --non-unique
This option permits to add a group with a non-unique GID.
-p, --password PASSWORD
The encrypted password, as returned by crypt(3). The default is to disable the
password.
Note: This option is not recommended because the password (or encrypted password) will
be visible by users listing the processes.
You should make sure the password respects the system's password policy.
-r, --system
Create a system group.
The numeric identifiers of new system groups are chosen in the SYS_GID_MIN-SYS_GID_MAX
range, defined in login.defs, instead of GID_MIN-GID_MAX.
-R, --root CHROOT_DIR
Apply changes in the CHROOT_DIR directory and use the configuration files from the
CHROOT_DIR directory.
-P, --prefix PREFIX_DIR
Apply changes in the PREFIX_DIR directory and use the configuration files from the
PREFIX_DIR directory. This option does not chroot and is intended for preparing a
cross-compilation target. Some limitations: NIS and LDAP users/groups are not
verified. PAM authentication is using the host files. No SELINUX support.
CONFIGURATION
The following configuration variables in /etc/login.defs change the behavior of this tool:
GID_MAX (number), GID_MIN (number)
Range of group IDs used for the creation of regular groups by useradd, groupadd, or
newusers.
The default value for GID_MIN (resp. GID_MAX) is 1000 (resp. 60000).
MAX_MEMBERS_PER_GROUP (number)
Maximum members per group entry. When the maximum is reached, a new group entry (line)
is started in /etc/group (with the same name, same password, and same GID).
The default value is 0, meaning that there are no limits in the number of members in a
group.
This feature (split group) permits to limit the length of lines in the group file.
This is useful to make sure that lines for NIS groups are not larger than 1024
characters.
If you need to enforce such limit, you can use 25.
Note: split groups may not be supported by all tools (even in the Shadow toolsuite).
You should not use this variable unless you really need it.
SYS_GID_MAX (number), SYS_GID_MIN (number)
Range of group IDs used for the creation of system groups by useradd, groupadd, or
newusers.
The default value for SYS_GID_MIN (resp. SYS_GID_MAX) is 101 (resp. GID_MIN-1).
FILES
/etc/group
Group account information.
/etc/gshadow
Secure group account information.
/etc/login.defs
Shadow password suite configuration.
CAVEATS
It is usually recommended to only use groupnames that begin with a lower case letter or an
underscore, followed by lower case letters, digits, underscores, or dashes. They can end
with a dollar sign. In regular expression terms: [a-z_][a-z0-9_-]*[$]?
On Debian, the only constraints are that groupnames must neither start with a dash ('-')
nor plus ('+') nor tilde ('~') nor contain a colon (':'), a comma (','), or a whitespace
(space:' ', end of line: '\n', tabulation: '\t', etc.).
On Ubuntu, the same constraints as Debian are in place, with the additional constraint
that the groupname cannot be fully numeric. This includes octal and hexadecimal syntax.
Groupnames may only be up to 32 characters long.
You may not add a NIS or LDAP group. This must be performed on the corresponding server.
If the groupname already exists in an external group database such as NIS or LDAP,
groupadd will deny the group creation request.
EXIT VALUES
The groupadd command exits with the following values:
0
success
2
invalid command syntax
3
invalid argument to option
4
GID not unique (when -o not used)
9
group name not unique
10
can't update group file
SEE ALSO
chfn(1), chsh(1), passwd(1), gpasswd(8), groupdel(8), groupmod(8), login.defs(5),
useradd(8), userdel(8), usermod(8).
shadow-utils 4.8.1 02/06/2024 GROUPADD(8)
Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
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