groupmod(1M)groupmod(1M)NAMEgroupmod - modify a group on the system
alternate_password_file] gid name] userlist] group
The command modifies a group on the system by altering the appropriate
entry in the file.
The command must be used with the group argument, which is the name of
the group to be modified. The name consists of a string of printable
characters that may not include a colon or newline
Refer to usergroupname(5) to understand the functionality changes with
the Numeric User Group Name feature.
The command uses the following options:
Specify the path to the alternate password file. When this
specified, user information is looked up in this file,
If specified, the option should used as the first
Change the value of the group
ID to gid. gid must be a non-negative decimal integer
less than as defined in the header file.
Allow the gid to be non-unique (that is, a duplicate).
Change the name of the group to
name. name consists of a string of printable charac‐
ters that may not include a colon or newline
Add userlist to the supplementary group membership list of
group. It should be used in conjunction with option.
Modify the supplementary group membership list of
group to userlist. It should be used in conjunction
Delete userlist from the supplementary group membership list
of group. It should be used in conjunction with
Specifies the list of users for modifying the supplementary
group membership list of the group. When options and
options are not specified, is assumed.
The command is aware of NIS user entries. Only local groups may be
modified with Attempts to modify an NIS group will result in an error.
NIS groups must be administered from the NIS server. If is used on a
system where NIS is installed, it may fail with the error
(return value 6) if the group specified is an NIS group (see group(4)).
However, NIS groups are checked when verifying uniqueness of the new
gid or new group name, which may result in the above error, or the
(return value 4).
The command exits with one of the following values:
Invalid command syntax.
Invalid argument supplied to an option.
gid is not unique (when is not used).
does not exist.
is not unique.
Cannot modify the
file busy. Another command may be modifying the file.
Unable to open
file or the file is non-existent.
Exceeding permissible limit of maximum members in a group.
The file is not modified.
Change the group ID of the group to in the file if the group exists.
This is done even if the group ID is already in use.
Change the name of to in the file if the group does not already exist.
Because many users try to write to the file simultaneously, a password
locking mechanism was devised. If this locking fails after subsequent
FILESSEE ALSOusers(1), groupadd(1M), groupdel(1M), logins(1M), useradd(1M),
userdel(1M), usermod(1M), group(4), usergroupname(5).