groupadd
create a new group
see also :
chfn - chsh - passwd - gpasswd - groupdel - groupmod - useradd - userdel - usermod
Synopsis
add an example, a script, a trick and tips
examples
source
groupadd squid
useradd -g squid squid
source
groupadd bbyo_ems_admin
groupadd bbyo_tsh_admin
groupadd bbyo_tsh_user
source
chroot . getent group bumblebee >/dev/null 2>&1
|| chroot . groupadd bumblebee
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.
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.).
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.
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).
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
files
/etc/group
Group account information.
/etc/gshadow
Secure group account information.
/etc/login.defs
Shadow password suite configuration.
see also
chfn ,
chsh , passwd , gpasswd ,
groupdel , groupmod ,
login.defs, useradd , userdel ,
usermod .