名称

       groupadd - 创建一个新组

大纲

       groupadd [选项] group

描述

       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.

选项

       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
           现实帮助信息并退出。

       -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
           此选项允许添加一个使用非唯一 GID 的组。

       -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.

           您应该确保密码符合系统的密码政策。

       -r, --system
           创建一个系统组。

           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.

配置文件

       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).

           默认值是 0，意味着组中的成员数没有限制。

           此功能(分割组)允许限制组文件中的行长度。这对于确保 NIS 组的行比长于 1024 字符。

           如果要强制这个限制，可以使用 25。

           注意：分割组可能不受所有工具的支持(甚至在 Shadow 工具集中)。您不应该使用这个变量，除非
           真的需要。

       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).

文件

       /etc/group
           组账户信息。

       /etc/gshadow
           安全组账户信息。

       /etc/login.defs
           Shadow 密码套件配置。

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.

退出值

       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

参见

       chfn(1), chsh(1), passwd(1), gpasswd(8), groupdel(8), groupmod(8), login.defs(5),
       useradd(8), userdel(8), usermod(8).